28 
THE YOYAGE OF H.M.S. CHALLENGER. 
Willemoes Sulim lias described the colour of this species in the living state 1 as being 
white with black spots. The black pigment I discovered by transverse sections to be 
placed in a layer beneath the epidermis, intersected by fibrils which are especially de- 
veloped on the dorsal side, and indeed disappear entirely on the ventral side (fig. 3, cu.). 
The ventral side (figs. 1, 2) is of an even brownish tint, and shows a central elevation 
corresponding to the ventral ganglion and central muscular mass, with its continuations 
towards the mouth (m. ) and cloaca (cl.), and radial elevations corresponding to the muscle 
bundles which run from the central muscle mass to the parapodia (p.) and suckers (s.). 
The parapodia (p.) are highly developed, and placed close to the external margin, in 
consequence of which their extremities are to be seen from above. The hooks (fig. 15) 
are very strong, measuring ’17-22 mm. in length, and up to '03 mm. in thickness; the 
tip is bent at a right angle. The column of the manubrium is very short (fig. 16), not 
much more than half as long as the hook. The manubrium (met.) is highly developed, 
and made up of three shovel-shaped prongs. 
The suckers (.s.) are placed between the bases of the parapodia and the margin of the 
body ; sometimes they project considerably, but are usually depressed as shown in fig. 3, 
where the sucker occupies., half the thickness of the body, and is entirely retracted into 
its sheath (s.). The epithelium covering the sucker ( se .) is markedly thicker than that 
over the rest of the body (e.). The free margin of the sucker has in some individuals a 
crown of brownish papillae, which are also occasionally found upon the parapodia. Viewed 
with a lens they look like ckitinous spicules, but are really only elevations of the integu- 
ment coloured brown by the enclosed pigment. In some individuals these struc- 
tures can be seen with the naked eye, in others the papillae appear to be absent or 
present, but without any pigment. The pharynx is relatively small, and the mouth (m.), 
also small, is some way removed from the margin of the body. The obtusely-conical 
cloacal papilla (cl.) is placed immediately beneath the hinder end of the body. This ven- 
tral situation of the cloaca is the most remarkable difference between this species and 
Myzostoma glabrum. 
The sexual organs resemble those of the last-mentioned species, and the young are 
attached to the body of the adult in the same way (see Genus Myzostoma, p. 63). 
The diffuse brown coloration of the young specimens is remarkable, resembling that of 
some adult specimens of Myzostoma glabrum (loc. cit., pi. i. figs. 3, 4). 
Host. — Uncertain. Dredged by Challenger Expedition at Stations 186, 187 (Cape 
York). The specimens, according to the notes of P. H. Carpenter, most probably come 
1 “ In der Anfura-See habe ich im vorigen Jahre einmal 80 Exemplare einer grossen Comatula untersucht und fand 
'•irca auf jeder zehnten unsere Schmarotzer. Es ist das das grosste Myzostomum, das ich je gesehen habe. Sie sassen 
oder krochen schlangelnd auf den Kelchen, selten in der Rinne der Arme. Meist fanden sich 2-3 grosse Thiere und 
mit ihnen ein kleineres. Alle diese Myzostomcn waren, wie die Comatula, weiss und schwarz gefleckt, und die iibrigen 
zahlreichen Schmarotzer des Thieres zeigten dieselbe Farbung.” — Yon der Challenger-Expedition, Brief VI. Zeitschr. 
f. wins. Zool. Bd. xxvi. p. lxxix. 
