OF SOUTHERN INDIA. 433 
The great relation of Gastropteron to Lobiger and other Oxyrvonrpm makes it, 
as I shall subsequently mention, probable that this genus belongs to the present 
family, but as the former is again closely allied to Aglaia (Doridium) and to 
Chelidonura, it becomes very difficult to draw a line between the Oxrworrp# and 
the Parzrvemz. Comparing the animal of Oxynoe with that of many Parzrwrrpz, 
the lateral edges of the foot are in both found equally to cover the sides of the shell, 
and the animal of Oxynoe crawls about like that of Philine ; the only real difference 
rests, therefore, in the dentition, which is very peculiar in the Parzrermz. It 
would probably be better to retain the Oxywozzpx only as a sub-family in the 
PHILINEIDA. 
Fossil species of OxYNOEID# are hardly known. Philippi noticed two Oxynoe from the upper 
tertiaries of Sicily. Deshayes’ Bulla goniophora (Paris foss., 2nd. ed., pl. 38, figs. 26-29) is an 
Akera. If we, however, find perfect impressions of Meduse preserved even in jurassic rocks, it is 
by no means improbable that the shells of the OxyvoziD£ may in time be found numerously 
represented among cretaceous fossils. 
LXI. Family,— PHILINEID ZZ. 
H. and A, Adams, Gen. II, p. 24, ex parte ; Gray, Guide, 1857, p. 191. 
The animals are of large size, having the tentacles united with the fleshy 
head-disk, which occasionally is emarginated posteriorly. The sides of the foot 
are dilated and cover the shell, often thus becoming internal, being more or less 
hidden under the mantle; the gizzard is provided with strong, calcareous plates. 
The dentition consists of two large hook-like, converging teeth, which sometimes 
have one much smaller on the outer side. 
Shell internal or external, thin, consisting of few very rapidly increasing whorls, 
the spire being sometimes reduced to a mere point; aperture very large, margins 
entire, outer margin often somewhat produced. 
The principal characteristic of the shell of the Pazzrvrrpz is the small num- 
ber of whorls, the last of which expands into a very large aperture. I do not 
think the fact of the shells being internal or external can absolutely be of very 
great importance, for it seems to depend entirely upon the local development 
of the mantle whether this covers the shell partially or totally. In the former 
case, the exposed part of the shell will be more solid; in the latter, the entire shell 
will be chiefly membranaceous. 
The following genera have to be placed, therefore, in this family :— 
1. Gastropteron, Meckel, 1818. Body small with very large lateral expan- 
sions of the foot. Krohn says (Archiv f. Naturgeschichte, 1860-61, XXVI, 
p. 64, etc.) that the embryonal shell of Gas. Meckelii is spiral, consisting of one 
and a half rapidly increasing whorls; the shell of the full grown animal is almost 
only represented by a very thin, chitinous membrane, lying under the mantle 
covering the viscera and in front extending nearly to the head. This large 
membranaceous shell terminates in a spiral, caleareous point, which lies on the 
right side of the visceral region, nearer to the ventral side. Thus in form the 
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