Phylum Nemertea (Rhynchocoela)
Phylum Nemertea (Rhynchocoela) Phylum Nemertea (Rhynchocoela)
Development Paleonemertea, Hoplonemertea, Bdellonemertea – direct development within eggs Heteronemerteans- produce free-swimming planktotrophic larva, pilidium. It is somewhat similar to a trochophore but lacks anus. Pilidium with incomplete gut, mouth between a pair of ciliated lobes (A). Ectodermal invaginations pinch off internally to produce the adult ectoderm(B). Juvenile metamorphoses in the larval skin during the planktonic stage(C). Skin is shed and juvenile settles in the sediment Desor larva is a creeping form. Iwata larva is a swimming form of the former. These two larvae do not feed when they are in the larval stage. Brusca and Brusca (2002)
1) Emergence of juvenile nemerteans (Cerebratulus sp.) 2) 3) 4) Adult Cerebratulus
- Page 1 and 2: Phylum Nemertea (Rhynchocoela) Gree
- Page 3: Nemertean Bauplan “Functionally
- Page 6 and 7: Feeding and digestion Proboscis is
- Page 8 and 9: Comparison of Proboscis Types Credi
- Page 10 and 11: Circulation and Gas Exchange Nemert
- Page 12 and 13: Excretion and Osmoregulation 2 to 1
- Page 14 and 15: Cerebral organs of nemerteans Most
- Page 16 and 17: Epidermis Frontal gland Esophagus R
- Page 20 and 21: Late-stage Cerebratulus sp. Pilidiu
- Page 22 and 23: Nemertean Taxonomy Nemerteans are c
- Page 24 and 25: Are Nemerteans sister taxa with fla
Development<br />
Paleonemertea, Hoplonemertea, Bdellonemertea – direct development within eggs<br />
Heteronemerteans- produce free-swimming planktotrophic larva, pilidium. It is<br />
somewhat similar to a trochophore but lacks anus.<br />
Pilidium with incomplete gut, mouth between a pair of ciliated lobes (A). Ectodermal<br />
invaginations pinch off internally to produce the adult ectoderm(B). Juvenile<br />
metamorphoses in the larval skin during the planktonic stage(C). Skin is shed and<br />
juvenile settles in the sediment<br />
Desor larva is a creeping form. Iwata larva is a swimming form of the former.<br />
These two larvae do not feed when they are in the larval stage.<br />
Brusca and Brusca (2002)
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