254 THE ANTARCTIC MANUAL. 
ing into the mouth of Trophonia wyvillei; the second is Prawillini- 
cola kréyerit, M‘Int., found on Prawilla abyssorum. 
MYZOSTOMIDA. 
The peculiar parasites grouped under this name are found only 
on Echinoderms, and, with the exception of one or two recently 
described cases, they are confined to the Crinoids. There are some 
seventy species, which are divided into two genera, Myzostoma, with 
all the species but one, and Stelechopus, of which there is but one 
species. Their habit of life varies. Some species crawl freely about 
their host, others are attached to the ventral surface, and their pre- 
sence causes more or less marked malformations of the neighbouring 
parts; others, again, form veritable galls, in which, like an insect in 
a plant-gall, several individuals pass their life. One species lives in 
the intestine of its host. 
The following were taken in our region:—(i.) Myzostoma com- 
pressum, von Graff, found on Bathycrinus aldrichianus, Wyv. Th., at 
station 146. (ii.) IZ. coronatum, von Graff, found on the same host 
at the same station. (ili.) Stelechopus hyocrini, von Graff, found on 
Hyocrinus bethellianus, Wyv. Th. and on B. aldrichianus, at station 
147. It is interesting to note that the ancient form Hyocrinus has a 
special genus of parasite unknown on other Crinoids, though these 
are abundantly infested with a great number of varied forms. It is 
also interesting to note that von Graff regards this genus “as un- 
doubtedly the lowest form of the Myzostomida.” 
GEPHYREA. 
The two genera of Unarmed Gephyrea, SrpuNcULOIDEA, which 
have been found at great depths are Phascolion and Phascolosoma. 
Several specimens of (1.) Phascolosoma pudicum, Sel., were found round 
Kerguelen, but at no great depths. (ii.) Phascolion lutense, Sel., was, 
however, brought up in the dredge at stations 156 and 157 from 
nearly 2000 fathoms. It has a thin, transparent, colourless skin. 
No specimen of Armed Gephyrean or ECHIUROIDEA was taken in our 
area, but it is perhaps worth mentioning that Echiwrus chilensis has 
been taken in. the Straits of Magellan. This genus is the one most 
common in the colder waters of the globe. 
NEMATODA. 
Very few Entozoa are known from great depths, though there 
seems no reason why internal parasites should not flourish as well in 
