REPORT ON THE MY ZOSTOMID A. 
49 
37. Myzostomci dentatum, n. sp. (Pl. IX. fig. 1). 
Of this elegant species I have but a single example, which is, fortunately, well 
preserved. The body is regularly elliptical, 1’9 mm. in length, and 1 ‘25 mm. in diameter. 
It is thin and delicate, and has a membranous appearance. The central part alone 
crowned by the bases of the parapodia, is somewhat thicker and of a brownish colour. 
The outer extremities of the ramified intestinal caeca (i.) are distinctly visible, and 
sharply marked off from this part of the body is the brownish-yellow border, which is 
•19 mm. in diameter. Instead of cirri there are a number of obtuse teeth-like serrations 
upon the border, which measure at most T36 mm. long; they are irregular in size and 
number. There are twenty to thirty larger ones, and between them a number of smaller 
projections, one of which lies in the middle line just at the anterior end of the body, 
and another in the middle line at the posterior end. 
The small rounded suckers ( s .) lie in the middle of the lateral margins of the body 
and occupy about one-third of them. The strong parapodia (p.) lie entirely within the 
central part of the body, which is occupied by the intestinal cseca ; the broad obtuse 
terminations are prominent only in some of them. On the margin of the central part 
above the third parapodium is visible on either side the large vesicula seminalis (vs.)] on 
the hinder margin of the central part is the cloaca (cl.). The mouth (to.) lies cpiite on the 
border of the body. The bulbus musculosus (ph.) of the pharynx is of extraordinary 
size — one-third of the length of the body. 
Host. — Antedon bidentata, P. H. C., from Station 186 (Torres Strait) of the Chal- 
lenger Expedition. 
38. Myzostomci Jimbriatum, n. sp.-(Pl. VI. figs. 5, 6). 
I had only one specimen, which measured about 1'8 mm. in length and 1'5 mm. in 
breadth. Though much damaged it appeared to resemble Myzostoma cirriferum in form, 
colour, size, and arrangement of parapodia and suckers. The suckers, however, are round, 
and there is a distinct male genital papilla on either side between the third parapodium 
and the margin of the body, which is about half the size of one of the parapodia. The 
border of the body is not transparent, and is not so sharply marked off as in Myzostoma 
cirriferum ; the twenty cirri are relatively shorter, the largest measuring only ’08 mm. 
The most striking feature is the tufts of fine hairs, ‘02 mm. long, on the margin of the 
body (5, a). They were only well preserved on one part of the specimen ; highly magni- 
fied (fig. 6) they have the appearance of glass, and are clubbed or bent at the extremity. 
The insertion of their base into the tissue of the body proves that they are not mere 
cuticular formations. 
Host. — Antedon eschrichti, Mull., sp., or Antedon quadrata, P. H. C., from Station 
48 (South of Halifax) of the Challenger Expedition. 
(ZOOL. CHALL. EXP. PART XXVII. 1884.) 
Dd 7 
