10 
Huxley on Lacijiularia socialis. 
"gills." Professor Ehrenberg, however, has not produced 
any evidence of such in-going currents, and Dujardin has 
denied their existence. So far as has yet been observed, 
the calcar is in immediate connection with the nervous 
ganglion. Melicerta affords a very good opportunity for ex- 
amining the structure of the organs, of which in this genus 
there are two. It is a somewhat conical process of the in- 
tegument, containing a similar process of the internal mem- 
brane. This, however, stops short a little distance from the 
extremity, and forms a transverse diaphragm, from the centre 
of which a bunch of long and excessively delicate setae pro- 
ceeds (fig. 29). I could observe no trace of any aperture with 
a power of 600 diam., though of course this is merely negative 
evidence. 
Is it not possible that, as the " ciliated sac " of the Asci- 
dians has its analogue in the " fossa " of the Rotifera, so the 
calcar may answer to the " languet," which has a similar 
relation to both sac and ganglion ? 
In Notommata there is no calcar, but nervous cords proceed 
from the ganglion to the ciliated spots about the middle of 
the dorsal surface (Dalrymple). 
Reproductive Organs. — Considering Professor Ehrenberg's 
determination of the male organs to be set aside, his descrip- 
tion of the reproductive organs extends only to the ovary, 
which, he says, in Lacinularia " lies in the posterior cavity 
of the body, and has thus one and the same outlet with the 
intestine " (p. 403). This seems to imply an oviduct; I 
could, however, see no such organ.* The ovary consists of 
a pale, slightly granular mass of a transversely elongated form 
(fig. 5 Z), and somewhat bent round the intestine ; it is 
enclosed within a delicate transparent membrane, which is 
hardly visible in the unaltered state, but becomes very obvious 
by the action of acetic acid, which contracts the substance of 
the ovary and throws the membrane into sharp folds. 
Pale clear spaces, which sometimes seem to be limited by 
a distinct membrane, are scattered through the substance of 
the ovary, and in each of these a pale circular nucleus is 
contained. The nucleus is more or less opaque, but usually 
contains 1-3 clear spots (fig. 9). 
These are the germinal vesicles and spots of the future 
ova. Acetic acid, in contracting the pale substance, groups 
it round these vesicles, without, however, breaking it up into 
separate masses. It renders the nuclei more evident. 
* Leydig (1. c, p. 469) says that there is a wide oviduct which becomes 
folded when empty. I must leave the discrepancy until a further exami- 
nation decides which is right. 
