A Review of the Genus Eunice - Smithsonian Institution Libraries

324 SMITHSONIAN CONTRIBUTIONS TO ZOOLOGY
Prostomium (Figure 110c) distinctly shorter and narrower
than pcristomium, less than V2 as deep as peristomium.
Prostomial lobes frontally rounded, dorsally inflated; median
sulcus deep. Antennae in a horseshoe, with A-I isolated by a
gap, similar in thickness. Ceratophores ring-shaped in all
antennae, without articulations. Ceratostyles tapering, with up
to 6 cylindrical articulations of varying lengths in A-III. A-I to
posterior peristomial ring; A-I I and A-III to setiger 1.
Peristomium as wide as anterior part of body, cylindrical, with
distinct muscular lower lip. Separation between rings well
marked dorsally and less distinct ventrally; anterior ring - 4 /5 of
total peristomial length. Peristomial cirri to middle of anterior
peristomial ring, slightly inflated basally, with 5 articulations.
Maxillary formula (illustrated in Mclntosh, 1885, plate 37:
fig. 20) 1+1,4+4, +0, 6+6, 1+1; Mx III absent in illustration,
but here assumed present in specimen.
Branchiae (Figure 110a) present, pectinate, distinctly longer
than notopodial cirri, not reduced in mid-body region, flexible.
Branchiae from setiger 4 or 5 to end of fragments. All branchiae
with 2 or more filaments; maximum 8 filaments. Branchial
stems tapering, flexible; filaments longer than stems, digitiform.
Neuropodial acicular lobes symmetrically triangular; aciculae
emerging at midline. Pre- and postsetal lobes low,
transverse folds. First 5 ventral cirri very large, digitiform.
Ventral cirri basally inflated from about setiger 6. Inflated
bases large, scoop-shaped (subacicular hooks emerging at
bases of scoops when they start); narrow tips tapering.
Notopodial cirri basally slightly inflated with 2 or 3 long,
indistinct articulations.
Limbate setae slender, marginally serrated. Pectinate setae
(Figure 110c) flat, flaring with thick shafts. All teeth similar in
length and thickness; -20 teeth present. Shafts of compound
falcigers (Figure 110b) long, essentially un-tapering, marginally
smooth. Appendages slender, tapering, bidentate. Proximal
teeth larger than distal teeth, triangular and directed laterally or
slightly distally. Distal teeth tapering, very nearly erect. Guards
asymmetrically bluntly pointed; mucros absent. Pseudocompound
falcigers and compound spinigers absent. Aciculae
paired, black, distally tapering, straight; cross-sections round.
Subacicular hooks (Figure HOd) black, bidentate. Hooks first
present from setiger 30, present in all setigers thereafter, always
single (except for replacements). Heads small; teeth similar in
size. Proximal teeth directed laterally, curved. Distal teeth
triangular, directed distally. Guards short and truncate.
UNKNOWN MORPHOLOGICAL FEATURES.—Structure of Mx
III and its relationship to left Mx IV; pygidium and anal cirri.
EXPECTED STATES OF UNKNOWN MORPHOLOGICAL FEA-
TURES.—MX III short, forming part of distal arc with left Mx II.
CHARACTERS USED IN PREPARATION OF KEY NOT
SCORED.—Inappropriate Characters: 56. Unknown Characters:
1, 2,4, 6, 13, 14, 36-38,40,42, 57-60, 63, 74, 78.
ASSUMED STATES FOR PURPOSE OF PREPARING KEY.—37,1;
38,1.
REMARKS.—The relationship between E. tribranchiata and
similar species in Australia was discussed by Fauchald (1986).
It is listed with similar species in Tables 27 and 29. Of the four
species with less than 10 branchial filaments where the
branchiae are fully developed listed in Table 29, two, E.
microprion and E. philocorallia, have peristomial cirri reaching
the middle of the prostomium; the two remaining species have
short peristomial cirri. The peristomial cirri arc articulated in E.
tribranchiata and lack articulations in E. plicata.
193. Eunice tridentata Ehlers, 1905
FIGURE 110f-l; TABLES 19, 21
Eunice tridenlala Ehlers. 1905:288-290. pi. 9: figi. 3-10— F«uch«ld,
1986:258-259. figs. 76-82.
MATERIAL EXAMINKD.—Holotypc, ZMH PE699. New Zealand.
DESCRIPTION.—Holotypc complete with 185 sctigers; total
length 170 mm; maximal width 7 mm at setiger 10; length
through setiger 10, 12 mm. Body circular in cross-section,
abruptly tapering anteriorly and slowly tapering posteriorly.
Prostomium (Figure 1100 distinctly shorter and narrower
than pcristomium, as deep as V2 of peristomium. Prostomial
lobes frontally rounded, dorsally inflated; median sulcus deep.
Antennae in a straight line, evenly spaced, similar in thickness.
Ceratophores ring-shaped in all antennae, without articulations.
Ceratostyles slender and digitiform, with up to 8 cylindrical,
distinct articulations in A-III. A-I to posterior margin of
peristomium; A-I I to setiger 2; A-III to setiger 3. Peristomium
a thick, cylindrical collar around prostomium; lower lip
distinctly scalloped, muscular. Separation between rings very
distinct both dorsally and ventrally, appearing nearly as a
separate segment, but indistinct laterally; anterior ring up 4 fc of
total peristomial length. Peristomial cirri nearly to tip of
prostomium, slender and tapering, without articulations.
Jaw apparatus missing.
Branchiae (Figure HOi) present, pectinate, distinctly longer
than notopodial cirri, not reduced in mid-body region, erect.
Branchiae from setiger 3 to setiger 80. Branchiae terminating
well before posterior end, present on less than 55% of total
number of setigers. First and last 15 pairs single filaments; all
other branchiae pectinate with maximum 14 filaments at setiger
30. Branchial stems soft, pliable. Filaments long and slender,
very much longer than notopodial cirri where best developed.
Anterior neuropodial acicular lobes asymmetrically rounded
with aciculae emerging above midline, near midline in
posterior setigers (Figure HOj). Posterior neuropodial acicular
lobes symmetrically conical. Anterior presetal lobes obliquely
transverse, sloping from a high point at dorsal margins towards
bases of acicular lobes at ventral margin. Anterior postsetal
lobes transverse low folds. Posterior pre- and postsetal lobes
follow outline of acicular lobes closely. First 4 ventral cirri
thick and sharply tapering. Ventral cirri with inflated bases