Acoelomates: Phylum Platyhelminthes and Nemertea - Biosciweb.net

Acoelomates: Phylum Platyhelminthes and Nemertea and 

Pseudocoelomates: Phyla Nematoda and Rotifera & Parasitism 6.1 

Lab #6 - Biological Sciences 102 – Animal Biology 

This lab is designed to explore the basic life history, physiology and adaptations of the 

acoelomate and pseudocoelomate animals with a focus on the Phyla Playthelminthes, Nemertea 

(Rhynchocoela), Nematoda, Rotifera. We will review the lifecycles of many of these species 

with an emphasis on their commonly parasitic nature. You must learn these lifecycles. 

Refer to chapters in the textbook for illustrations, diagrams, and 

additional information about acoelomates & pseudocoelomates. 

The Acoelomate Animals 

The acoelomates are animals that have no coelom (body cavity). They include flatworms, 

phylum Platyhelminthes (Gr. platys, flat, + helmins, worm); ribbon worms, phylum Nemertea 

(Gr. Nemertes, one of the Nereids, mermaids of Greek mythology); and jaw worms, phylum 

Gnathostomulida (Gr. gnathos, jaw, + stoma, mouth). In acoelomate animals, the space 

between the body wall (ectoderm) and digestive tract (endoderm) is not a cavity, as in 

coelomate animals, but is filled with muscle fibers and a loose tissue of mesenchymal 

origin, called parenchyma, both derived from mesoderm. The presence of a well-developed 

mesodermal layer makes the acoelomates triploblastic (having three germ layers: ectoderm, 

endoderm, and mesoderm). Flatworms are a large and economically important group because 

they include not only free-living planarians but also parasitic tapeworms and flukes. 

Acoelomates are more complex in organization than the radiate animals in several ways: 

‣ Acoelomates have bilateral symmetry 

‣ They have defined tissues organized into functional organs 

‣ They have a highly organized nervous system with concentration of nervous tissue and 

sense organs in the anterior end (cephalization) 

‣ They have an excretory system of specialized flame cells and tubules for elimination of 

nitrogenous wastes (breakdown products of protein, nucleic acid and other metabolism) 

‣ Platyhelminthes have a gastrovascular system, but ribbon worms have separated the 

two functions and have a complete mouth-to-anus digestive tract and a circulatory system 

‣ Flatworms have a tissue-organ level of organization 

Body Plan Features Retained by Acoelomates (seen in previously studied phyla): 

‣ true tissues present 

Body Plan Features & Characteristics of Members of the Phylum Platyhelminthes 

(not seen in the Phylum Cnidaria – some of these traits are seen in other animal phyla in 

addition to the Phylum Platyhelminthes): 

1. acoelomate 

2. bilateral symmetry 

3. triploblastic structure (endoderm, mesoderm and ectoderm) 

4. some degree of cephalization = head with sensory organs 

5. more organ systems (simple and formed of true tissues) are present 

6. flame cells in flame bulbs for excretion 

7. gastrovascular cavity for digestion and gas exchange (organs near body surface) 

8. longitudinal, circular and ventro-dorsal muscles 

9. hydrostatic skeleton (as muscles push against parenchyma and tissue fluids) 

10. high surface-volume ratio as a result of flat shape (Important in locomotion and in 

exchange of nutrients and wastes). 

11. monoecious (hermaphroditic) = male and female organs in one individual 

12. most are parasitic, but some are free-living




Classification & Adaptations of Acoelomate Animals 

Phylum Platyhelminthes (flatworms) 

Class Turbellaria (tur'bel-lar' e-a) (L. turbellae, stir, bustle, + aria, like or connected with). 

About 3000 species; Turbellarians. Mostly free-living, with a ciliated epidermis. A paraphyletic 

grouping. Example: Dugesia tigrina 

Class Monogenea (mon'o-gen'e-a) (Gr. mono, single, + gene, origin, birth). About 1100 species; 

Monogenetic flukes. Adult body covered with syncytial tegument without cilia; leaflike to 

cylindrical in shape; posterior attachment organ with hooks, suckers, or clamps, usually in 

combination; all parasitic, mostly on skin or gills of fishes; single host; monoecious; usually 

free-swimming ciliated larva. Examples: Polystoma, Gyrodactylus 

Class Trematoda (trem'a-to'da) (Gr. trematodes, with holes, + eidos, form). About 10,000 

species; Digenetic flukes. Adult body covered with nonciliated syncytial tegument; leaf-like or 

cylindrical in shape; usually with oral and ventral suckers, no hooks; development indirect, 

first host a mollusc, final host usually a vertebrate; parasitic in all classes of vertebrates. 

Examples: Fasciola, Clonorchis, Schistosoma 

Class Cestoda (ses-to'da) (Gr. kestos, girdle, + eidos, form). About 3500 species; Tapeworms. 

Adult body covered with non-ciliated, syncytial tegument; scolex with suckers or hooks, 

sometimes both, for attachment; long, ribbonlike body, usually divided into series of 

proglottids; no digestive organs; parasitic in digestive tract of all classes of vertebrates; first 

host may be invertebrate or vertebrate. Examples: Taenia, Diphyllobothrium 

Phylum Nemertea or Rhynchocoela (ribbonworms) 

About 600 species. Ribbon worms are often called nemertine or nemertean worms. Nearly all 

are marine and are characterized by an eversible proboscis that can be thrown out with great 

speed to capture food. Ribbon worms have separated the two functions of the gastrovascular 

cavity in flatworms and have a complete mouth-to-anus digestive tract and a circulatory 

system. Nemerteans occur in the intertidal, under stones or sea weed, or in burrows in muddy 

sand. Nemerteans can be very long at up to 50 meters (these species are the worlds 

longest animals). 

Body Plan Features & Characteristics of Members of the Phylum Nemertea 

(some of these traits are seen in other animal phyla in addition to the Phylum Nemertea): 

1. acoelomate, bilateral symmetry, triploblastic structure 


3. some organ systems (formed of true tissues) are present 

4. eversible proboscis (only worm phylum with this characteristic) 

5. complete digestive tract/system (from mouth-to-anus) 

6. separate circulatory system with two lateral vessels on each side of the gut and 

sinuses around head and tail; no definite closed circulation 

7. flame cells for excretion 

8. longitudinal and circular muscles contract against fibrous basement membrane; 

multiple patterns of muscle fiber organization 


10. dioecious with sexual reproduction or asexual fragmentation 

11. not parasitic, free-living




The Pseudocoelomate Animals 

All bilateral animal phyla except the acoelomates possess a body cavity belonging to one of 

two types: (1) true coelom, in which a peritoneum (an epithelium of mesodermal origin) 

covers both the inner surface of the body wall and the outer surface of the visceral 

organs in the cavity, or (2) pseudocoel, a body cavity not entirely lined with peritoneum (one 

layer of mesoderm attached to the ectoderm). 

A body cavity of either type is an advantage because it provides room for organ development 

and storage and allows some freedom of movement within the body. The cavity is often fluidfilled 

and provides for a hydrostatic skeleton in those forms lacking a true skeleton. 

There are nine pseudocoelomate phyla, of which phylum Nematoda is by far the largest. All 

pseudocoelomate phyla are at the organ-system level of organization. 

In general pseudocoelomates tend to be cylindrical in body form, to be unsegmented, and to 

have a complete (mouth-to-anus) digestive tract (this is absent in acanthocephalans). The 

epidermis is usually covered with a cuticle. There are both aquatic and terrestrial members, 

and parasitism is fairly common. 

Body Plan Features Retained by Pseudocoelomates (seen in previously studied phyla): 

1. presence of true tissues 





Body Plan Features & Characteristics of Pseudocoelomates: 

1. possess a pseudocoelom (mesoderm lines ectoderm tissue side only) 

2. they are unsegmented 

3. complete digestive tract/system (from mouth-to-anus) 

4. epidermis is covered with a cuticle




Classification & Adaptations of Pseudocoelomate Animals 

Phylum Nematoda (roundworms) 

More than 25,000 species. Roundworms. Nematodes are an extensive group with worldwide 

distribution. They include terrestrial, freshwater, marine, and parasitic forms. They are 

elongated roundworms covered with a flexible, nonliving cuticle. Circular muscles are lacking 

in the body wall and, in Ascaris, longitudinal muscles are arranged in four groups separated by 

epidermal cords (some nematodes have six or eight groups of longitudinal muscles). Cilia are 

completely lacking. Nematodes are found free-living in almost every conceivable habitat from 

arid deserts to lake bottoms, rivers, polar seas. Nematodes - both parasitic and freeliving - are 

incredibly abundant. A handful of good garden soil contains thousands of nematodes. Some 

50 different species of nematodes occur in humans, most of them nonpathogenic. Some 

nematodes are plant parasites feeding on plant sap, especially roots. 

Body Plan Features & Characteristics of Members of the Phylum Nematoda 

(some of these traits are seen in other animal phyla): 

1. pseudocoelomate 



4. psuedocoelomate = possess a pseudocoelom 



7. vermiform (worm-like) body shape 

8. complete digestive tract with three angled (longitudinal, circular and oblique) 

muscular pharynx, intestine lacking muscular walls, short rectum and anus 

9. excretion and osmoregulation through the cuticle and by excretory canals 

10. lack both cilia and flame cells/bulbs 

11. body wall lined with cuticle which retains body shape 

12. longitudinal muscles only, no circular muscles in body wall; body length or 

diameter does not change in movement 


14. dioecious; sexes separate with females larger than males; one or two tubular gonads; 

copulatory spicules present in males 

Phylum Rotifera (rotifers) 

There are about 2000 species of rotifers. The name "rotifer" is derived from the Latin word 

meaning "wheel-bearer"; making reference to the crown of cilia around the mouth of the rotifer. 

The rapid movement of the cilia in some species makes them appear to whirl like a wheel. 

Rotifers can be found in many freshwater environments and in moist soil. The habitat of 

rotifers may include still water environments, such as lake bottoms, as well as flowing water 

environments, such as rivers or streams. Rotifers are also commonly found on mosses and 

lichens growing on tree trunks and rocks, in rain gutters and puddles, in soil or leaf litter, on 

mushrooms growing near dead trees, in tanks of sewage treatment plants, and even on 

freshwater crustaceans and aquatic insect larvae. Most species of rotifers are about 200 to 500 

micrometers long. However a few species, such as Rotaria neptunia may be longer than a 

millimeter. Rotifers are thus multicellular creatures who make their living at the scale of 

unicellular protists. Characteristic features of rotifers include the ciliated corona ("wheel 

organ") and the mastax. The corona is located anteriorly and functions in locomotion and food 

gathering. The corona is modified extensively in some species. The mastax is a muscular 

pharynx containing a complex set of hard jaws or trophi and is found in all rotifers. These 

characteristics of these structures have been used extensively in classifying rotifers.




Body Plan Features & Characteristics of Members of the Phylum Rotifera 

(some of these traits are seen in other animal phyla): 

1. bilateral symmetry and triploblastic structure (endoderm, mesoderm and ectoderm) 

2. psuedocoelomate = possess a pseudocoelom 



5. complete digestive system with mouth and anus 

6. well muscularized pharynx = mastax that contains trophi (jaws) for sucking and 

grinding food particles 

7. ciliated corona helps sweep food particles to mouth 

8. pair of protonephridial tubules for osmoregulation & excretion 

9. syncitial (multinucleate) epidermis; some have a secreted cuticle 

10. longitudinal muscles and circular muscles in body wall 

11. pedal glands of foot secrete adhesive material in both sessile and creeping forms 


13. dioecious; sexes separate with females larger than males; one or two tubular gonads; 

copulatory spicules present in males; can be parthenogenic 

‣ Reproduction in Rotifers 

‣ single (male) or double set of gonads (female) and ducts in each sex 

‣ sexes separate (dioecious) 

‣ males unknown in class Bdelloidea and only occur a few weeks a year in the class 

Monogononta 

‣ all females are parthenogenetic in the class Bdelloidea (diploid females produce 

diploid females) 

‣ parthenogenesis = unisexual reproduction involving the production of young by 

females that are not fertilized by males; common in rotifers, aphids, bees, ants and 

wasps. Parthenogenetic eggs may be haploid or diploid. 

‣ in the class Monogononta, most of the year, diploid females produce thin shelled 

diploid amictic eggs. These amictic eggs develop parthenogenetically into diploid 

(amictic) females. When the environment in the pond or stream changes due to 

crowding, diet, change in photoperiod, etc. some amictic eggs develop into diploid 

mictic females that produce thin shelled haploid eggs. If these eggs are not fertilized 

then they will develop into haploid males. If the eggs are fertilized, they become 

mictic eggs with a thick, resistant shell and become dormant. These “winter eggs” 

can survive until the environment becomes more suitable at which time they hatch and 

develop into amictic females (completing the cycle). Females grow and reach maturity 

in a few days while males rarely grow and are mature at birth.




‣ Concepts Related to Parasitic Worms 

Basic Requirements for a Parasitic Life 

1. The parasite must have or obtain access to a host(s) 

2. The parasite must establish itself and survive within the host(s) 

3. The parasite must show successful reproduction and transmission to a new host 

Special Parasitic Adaptations 

1. Invasion of the host can occur through many mechanisms: 

a. through the mouth with food and/or water 

b. through the skin by penetration 

c. through a vector such as a biting insect 

2. Establishment and survival within a host requires: 

a. transport of parasites/larvae/eggs in host through blood or lymph 

b. resistance to host's defenses (such as resistance to immune cells, circulating 

antibodies and acids and enzymes in the digestive tract for intestinal parasites) 

3. Reproduction, by cross fertilization: 

a. most trematodes and cestodes are monoecious (both sexes in one individual) 

b. most nematodes are dioecious; generally, males are smaller than females 

4. Parasitic Worm Life Cycles 

SEE THE DETAILED HANDOUT AVAILABLE ON THE COURSE WEBSITE 

a. Fertilization occurs within a host and fertilization is internal as a result of 

copulation. The parasite zygote develops into a shelled embryo which develops 

into a larval stage(s). 

b. SIMPLE PATTERN (monogenes, some tapeworms, nematodes) 

ZYGOTE -----> LARVA -----> ADULT -----> MANY EGGS 

c. COMPLEX PATTERN (digenes and some tapeworms) 

ZYGOTE --> 1st LARVAL STAGE--> 2nd LARVAL STAGE--> 

3rd LARVAL STAGE --> ADULT --> MANY EGGS 

5. Digenetic trematodes and cestodes have specialized surfaces consisting of a 

cellular syncytium with microvilli (microtrichs) which serve to increase the 

absorptive surface up to 50 times. Membrane surface serves to protect against 

host's digestive enzymes, serves in chemical modification of absorbed 

solutes, and serves in membrane transport




‣ LIFECYCLES OF HELMINTHS (Worms) 

‣ TREMATODES (Class Trematoda) 

Clonorchis sinensis = The oriental liver fluke 

HOST (human) 

adult worm in liver 

shelled embryo 

miracidium 

SNAIL 

FISH 

metacercaria 

(in muscle) 

cercaria 

redia 

sporocyst 

Schistosoma mansoni -- Blood fluke 

HOST (human) 

adult worm in 

liver 

shelled embryo 

miracidium 

cercaria 

sporocyst 

SNAIL 

‣ CESTODES (Class Cestoda) 

Taeniarhynchus saginatus - The beef tapeworm 

ADULT HOST (humans) 

adult worm in intestine 

shelled embryos 

in proglottid 

consumed with 

grass by cattle 

cysticercus (bladder worm) 

in beef muscle 

onchospheres 

in blood




‣ NEMATODES (Phylum Nematoda) 

Ascaris lubricoides = intestinal roundworm 

Ascaris lumbricoides -- Intestinal roundworm 

Adults (male & female) 

in human intestine 

shelled embryos 

in feces 

shelled larvae 

develop (10-15 

days) on soil. 

in lung, larvae leave 

blood, move to 

trachea, esophagus 

larvae emerge in 

duodenum, penetrate gut 

wall and enter blood stream 

shelled larvae 

ingested by humans 

with food or water 

Ancylostoma duodenale = hookworm 

Ancylostoma duodenale -- Hookworm 

Adults in human 

intestine 

thin shelled embryos in feces 

larvae develop, 

hatch in soil 

esophagus 

larvae grow, 

feed on feces 

bronchi 

in lung, larvae leave 

blood, enter alveoli 

larvae attach, 

penetrate skin, 

enter blood stream 

Enterobius vermicularis = pinworm 

Enterobius vermicularis -- Pinworm 

Adults (male & female) 

in human large intestine 

and cecum 

females migrate to 

anus at night 

deposited shelled 

embryos cause itching 

hatch in duodemum 

reinfection of self, 

others, water and food. 

Also in air or dust. 

fingernails and 

clothing pick up 

shelled embryos




LAB PROCEDURE 

NAME: 

LAB SCORE: 

Refer to the textbook and the internet to help you answer the questions. 

You must answer ALL questions in the lab procedure for full credit. 

Finish them at home if you do not have time to complete them in lab. 

Answer these questions: 

List some advantages of bilateral symmetry over radial symmetry? 

What advantages does cephalization offer for a bilateral animal? 

Acoelomates and pseudocoelomates have excretory systems of specialized flame cells or 

protonephridia for the elimination of nitrogenous wastes. How does a radiate animal, such as 

a hydra or sea anemone, rid itself of waste molecules? 

Cilia are completely lacking in nematodes. Are cilia present in any acoelomates? If so, 

during what life stage are the cilia often obvious? 

Are cilia present in any cnidarians?




Phylum Platyhelminthes 

Class Turbellaria = free-living flatworms 

‣ Observe the specimens and/or diagrams of the species listed below. 

‣ Record the descriptive information requested at the end of the lab for each species. 

‣ Dugesia sp., a triclad flatworm 

‣ an available polyclad flatworm 

‣ What are the two major orders of flatworms in the Class Turbellaria? 

‣ Observations of a Free-Living Planarian Flatworm 

‣ Obtain a living specimen of Dugesia tigrina or Planaria sp. as available in a small 

petri dish or watch glass and study it under the dissecting microscope. 

Species name of your observed specimen: 

‣ Note the gliding movement. What causes it? 

‣ Using forceps, gently turn your flatworm over. Observe and describe the righting response. 

‣ How long does the righting response take? 

‣ Does the worm avoid obstacles such as a needle or probe without touching them? 

‣ Locate the eyespots and the “ears” or auricular organs. These organs contain 

chemoreceptors for detection of specific molecules (eg. “smell”/olfaction). Place a small 

piece of liver in the dish and observe and record how the worm responds.




‣ Do you think the response to the liver depends on the presence of the auricular organs? 

‣ Briefly describe how you could test your hypothesis? 

‣ Does the worm respond to differences in light intensity? Record your observations below. 

‣ Record the reaction of the planarian to the addition of one drop of a 0.1% salt solution 

placed in front of it. 

‣ How do the two major types of turbellarian (Class Turbellaria) flatworms differ? (eg. How do 

members of the Order Tricladida (triclad flatworms) differ from members of the Order 

Polycladida (polyclad flatworms – how are their bodies different)?




‣ Observations of Planarian Flatworm Body Structures 

‣ Using a microscope and the preserved, prepared slides identify the following structures of 

Dugesia sp.or Planaria sp. 

‣ Draw and CLEARLY label the Dugesia sp.or Planaria sp. whole mount. 

‣ eyespots 

‣ intestine 

‣ auricular organs 

‣ pharynx 

‣ Draw and CLEARLY label the Dugesia sp.or Planaria sp. cross section through the 

pharynx. 

‣ intestine 

‣ diverticula 

‣ epidermis 

‣ pharynx 

‣ cilia 

‣ nerve cords 

‣ circular muscles 

‣ longitudinal muscles 

‣ Planaria Regeneration Experiments 

‣ Your instructor may perform incisions on some planarian flatworms to demonstrate 

regeneration. We will culture and observe these specimens in lab over the next few weeks.





Class Trematoda = flukes 


‣ Record the descriptive information requested at the end of the lab for this species. 

‣ Opisthorchis (Clonorchis ) sinensis = human liver fluke 

‣ Observations of Trematode Body Structures 


trematodes. 

‣ Draw and CLEARLY label the Opisthorchis (Clonorchis) sinensis. whole mount. 

‣ oral sucker 

‣ ventral sucker 

‣ pharynx & intestines 

‣ excretory canals/ducts 

‣ uterus 

‣ ovary (as visible) 

‣ yolk gland (as visible) 

‣ anterior & posterior testes 

‣ vas deferens (as visible) 

‣ seminal receptacle (as visible) 

‣ bladder 

‣ Why do you think this species lacks a complete gut (it has only one opening, not really 

an anus)? 

‣ Then why is a gut/intestine present at all?




‣ Observation of an Example of Trematode Copulation 

‣ Draw the male and female Schistosoma mansoni in copulation from a prepared slide 

indicating which sex is which. 

‣ What aspect of their reproduction is unusual with respect to other trematode species? 


Class Cestoda = tapeworms 

‣ Observe the specimens and/or diagrams of the 

species listed below. 

‣ Record the descriptive information requested at the 

end of the lab for this species. 

‣ one adult cestode tapeworm on display 

‣ Observation of Cestode Body Structures 


cestodes. 

‣ Examine a prepared slide of a scolex (head) from a tapeworm such as Taenia sp. or 

Diplidium sp. . 

‣ Sketch and label the scolex. Label the four suckers, and the hooks. 

‣ Examine a slide of a gravid proglottid of a cestode. Note the following structures: 

(you do not need to draw this, but you should be able to identify these in a diagram) 

‣ nerve cords (as visible) 

male reproductive structures are not easily 

‣ excretory canals 

visible in a gravid proglottid 

‣ vagina/genital pore 

‣ Note how the ova are packed into the branched uterus 

‣ Roughly, how many eggs are their per gravid proglottid? 

(are there 10s, 100s, 1000s, millions of eggs per gravid proglottid?)




Phylum Nemertea (Rhynchocoela = ribbonworms) 



‣ Baseodiscus punneti or other 

‣ List one anatomical structure seen in nemerteans that is not seen in other types of 

aceolomate or pseudocoelomate worms. 

Phylum Nematoda (roundworms) 



‣ Ascaris lumbricoides = human intestinal parasite 

‣ Observation of Nematode Body Structures 


cestodes. 

‣ Examine a prepared slide of Ascaris lumbricoides male and female. Note the 

following structures: (you do not need to draw this, but you should be able to 

identify these in a diagram) 

‣ epidermis 

‣ cuticle 

‣ muscle cells & processes 

‣ intestine 

‣ pseudocoel 

‣ longitudinal muscles 

‣ lateral lines/nerve cords 

‣ excretory canals (as visible) 

‣ In the female Ascaris cross section locate the following: 

‣ ovary 

‣ oviduct 

‣ uterus Can you recognize the ova? 

‣ In the male Ascaris cross-section (on the same slide) locate the : 

‣ testes 

‣ vas deferens (as visible) 

‣ Observation of a Free-Living Nematode Roundworm 

Obtain a sample of living “vinegar eels”, Turbatrix aceti, and examine under the 10X 

objective and the 20X or 40X of the compound microscope. You should add Proto-Slo 

to the preparation before adding the cover slip. 

‣ Note the direction of movement, which is actually dorso-ventral (rather than 

lateral) bending. 

‣ What is it about the muscular structural arrangement in nematodes that permits 

only this characteristic “whip-like” motion?




‣ Is the reproductive cycle of Turbatrix aceti as complex as that of Ascaris 

lumbricoides? Why, or why not do you think this is the case? Look this up in the text 

or on the Internet. 

Phylum Rotifera (rotifers) 



‣ a rotifer (you will probably be unable to identify it to species, so just provide a 

common name) 

‣ Examine the culture of rotifers. Examine a sample on a slide with Proto-Slo under 

the compound microscope. 

‣ Draw and CLEARLY label the following rotifer structures, otherwise be able to 

identify the following structures: 

‣ corona 

‣ mastax (jaw apparatus) 

‣ trochus (ciliated whorls) 

‣ stomach 

‣ intestine 

‣ mouth 

‣ foot and toes (for anchoring) 

‣ cloacal bladder (as visible) 

‣ pedal glands (as visible) 

‣ eyespots near brain (as visible)




For the live specimens available for observation in the lab, record the requested 

information. 


Class Turbellaria 

Order Tricladida 

Scientific name: Dugesia sp. or other 

Common name: 

General dimensions of specimen: 

Unique structures or features: 

Draw a simple sketch to remind you of the basic structure of this species and any unique 

characteristics observed. 

Notes & observations to help you remember and distinguish this group/species:





Class Turbellaria 

Order Polycladida 

Scientific name of a polyclad turbellarian: 

Common name: 










Class Trematoda 

Scientific name: Opisthorchis (Clinorchis) sinensis or other 

Common name: 





Notes & observations to help you remember and distinguish this group/species: 

Fluke lifecycle





Class Cestoda 

Scientific name: 

Common name: 





Notes & observations to help you remember and distinguish this group/species: 

Pig Tapeworm Lifecycle




Phylum Nemertea (Rhynchocoela) 

Class (check ITIS): 

Scientific name: Baseodiscus punneti or other 

Common name: 









Phylum Nematoda 


Scientific name: Ascaris lumbricoides 

Common name: 









Phylum Nematoda 



Common name: Vinegar Eels 









Phylum Rotifera 



Common name: 









LABORATORY NOTES: 

Platodes by Haeckel




LABORATORY NOTES:

Acoelomates: Phylum Platyhelminthes and Nemertea - Biosciweb.net

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