54 
THE VOYAGE OF H.M.S. CHALLENGER. 
margin of the suckers ; the male genital openings ($ ), but little prominent, lie still 
further inwards. 
The largest specimen was dredged at St. Vincent (Station 224 of the “Blake” 
Expedition); it is 4 mm. in length, and considerably stouter and less transparent than 
the specimens described above. The intestinal zone is ribbed on the ventral side ; the 
intestinal branches form externally elevated crests. 
Host. — Actinometra jpulcliella, Pourt., sp., from Station 210 (Martinique) and Station 
224 (St. Vincent) of the “ Blake ” Expedition.. Another specimen came from Station 
269 (St. Vincent) of the “ Blake ” Expedition, and probably from Actinometra pulchella, 
which occurred also at this Station.. 
45. Myzostoma elegans , Graff.. 
Myzostoma elegans, Graff, Genus Myzostoma, p. 12, pi. x. figs. 1-3. 
I have only one specimen of this form, which was brought up by the “ Bibb ” Expe- 
dition, off French Reef, on Actinometra meridionalis. In diameter it was 2 mm.; the 
cirri were rather damaged. 
Hosts. — (a) Antedon triquetra, Semper, MS., Bohol (Philippines). 
(b) Actinometra parvicirra, Mull., sp., Bohol (Philippines). 
(c) Actinometra meridionalis, A. Kg., sp. “Bibb” Expedition, April 3, 1869, 
off French Ree£„ 
46. Myzostoma amtennatum ,. n.. sp. (PL. VIII. fig. l). 
I received a single specimen from the Kiel Museum. The figure I have given is some- 
what restored ; the edges were so folded and pressed together that I found it necessary 
to divide the animal longitudinally, and then to draw each separate half ; many of the long 
cirri which were injured by this process were completed by the help of their bases of attach- 
ment, and a comparison with the remaining intact cirri. The body is as stout as that of 
a well-developed Myzostoma cirriferum, and is darkish brown in colour ; the median part of 
the body is opaque, but the marginal zone between the suckers ( s . ) and the border is thinner 
and slightly transparent, without being distinctly marked off from the rest. In life the 
body must have been circular ; its length is 1 ‘4 mm. The parapodia (p.) are well-developed, 
and stand in the middle line between the centre and the margin ; the round conspicuous 
suckers are at about the end of the middle third of the radius. The mouth (to.) lies far 
inwards behind the foremost pair of parapodia ; the strong pharynx, provided with papillae, 
extends some way out of it. The cloaca (cl) is ventral in position, and lies in the more 
transparent marginal zone between the suckers and the edge of the body. The first, second, 
and last pairs of cirri are distinguished by their considerable length and size, as well as by 
their greater distance from each other. The first and last pairs are about. 1 mm. long, the 
