a Genus of quasiparasitic Mollusks. 323 
After the English version of these characters, a few more 
particulars are given,—viz. that the mantle is of a green hue, 
and has a small aperture at its base, and that on its ventral 
aspect is the rudiment of a foot. It is likewise mentioned that 
“Mr. Cuming found this elegant parasite burrowed in different 
parts of the rays of the oral disk of Asterias solaris. It is 
almost hidden from sight, so deeply does the animal penetrate 
into the substance of the Starfish, in which it makes a comfort- 
able cyst for itself, wherein it most probably turns by the aid of 
its rudimentary foot. All the specimens infested with Stylifere 
appeared to be in the best health. Though there is reason to be- 
lieve that they feed upon the juices of the Starfish, with that 
instinct of self-preservation imparted to all parasites, whose ex- 
istence depends upon that of their nidus, the Stylifer, like the 
Ichneumon among insects, appears to avoid the vital parts; for 
in no instance did Mr. Cuming find it imbedded anywhere save 
in the rays, though some had penetrated at their base, and very 
near the pelvis.” I must confess that 1 am not prepared to 
adopt this teleological mode of reasoning, so far as regards the 
Stilifer ; because it does not appear that the Starfish has, in the 
calcareous and solid parts inhabited by its so-called parasite, any 
internal juices or soft tissue on which the latter can feed. The 
investing membrane is wholly external. Although the above 
description of the animal was undoubtedly correct and circum- 
stantial, it must not be forgotten that it was drawn up from 
specimens which had been preserved for a considerable time in 
spirits. The examination of such specimens could not yield 
the same result, in a scientific point of view, as that of living 
individuals in their native habitat. 
Our best British malacologist, Mr. Alder, is the only one who 
has noticed the animal of S. Zurtont. The specimen which he 
examined was rather injured, and in a very sickly state. He 
says, ‘ It was white, had a rather large foot, without operculum, 
and a rounded head with two cylindrical tentacles, and minute 
eyes at the (external or posterior) base. No portion of the shell 
was covered by the fleshy parts ; but we are not prepared to say 
that, in a state of vigour, the animal has not the power of extend- 
ing some part of the mantle or foot over it. The remains of the 
animal, examined under a microscope, did not show any denticu- 
lated tongue.” (I may add, by way of parenthesis, that Mr. Alder 
has, within the last few days, examined the soft parts of two 
more individuals which I sent him for that purpose, but failed 
to detect any traces of a spinous tongue.) He also observed 
that “the otolites are circular, with a central dot, that the gill 
consists of a single series of triangular lobes, and that the mouth 
21% 
