152 Prof. G. J. Allman on the Anatomy of Acteon. 
seen to enter close to one another. One of these tubes, z, runs 
a little forwards, then bends backwards and bifureates, the divi- 
sions again bifurcating dichotomously: its ultimate distribution, 
however, I have not succeeded in tracing. The other tube, £, 
runs forwards to the oval body, z, just alluded to, into which it 
opens. This body is evidently furnished with a cavity ; its ante- 
rior half is of a peculiar complex structure, perhaps glandular, 
and destined for the elaboration of some definite secretion. From 
its anterior extremity a tube may be traced forwards till lost be- 
neath the edge of a large, irregularly-shaped, somewhat plicated 
body, y. In this body the tube would seem to terminate, though 
here I cannot speak with certainty. The sac, y, contains a yel- 
lowish semifluid secretion, which can be forced by the action of 
the compressor forwards into the oval body, z, and backwards 
through the bifureating tube, z. With the plicated body, y, 
which I would feel inclined to look upon as a testis, a pyriform 
sac, 6, is connected ; this sac contains a substance of a semifluid 
consistence, and is furnished with a long neck, which can be 
traced into the plicated body ; but whether it termimates here or 
is continued to some external outlet, I have been unable to satisfy 
myself. 
Occupying the great lateral expansions, and placed immediately 
beneath the ramified organ already described in connexion with 
the digestive system, is a curious and very complicated body, €&€. 
This body, which is perhaps an ovary, is double, being formed of 
two perfectly similar portions, one of which is placed in each 
branchial expansion, and consists of a delicate tube dichotomously 
ramified, and furnished along its entire length with closely-set 
sacciform appendages, Pl. VII. fig. 8 a. These contain a granular 
substance, but whether they communicate with the interior of the 
tube is not very manifest. Besides these appendages, numerous 
spherical capsules, Pl. VI. @ 6, and Pl. VII. fig. 86, may be seen 
arranged at tolerably regular intervals along the tube, and appa- 
rently communicating by means of a short neck with its interior. 
These capsules inclose a number of oval bodies, Pl. VII. fig. 8 ce, 
and fig. 7, in each of which is a granular mass surrounding a 
very distinct nucleus, which is placed towards one extremity, and 
is itself furnished with a secondary nucleus. The connexion be- 
tween this curious system and the other parts of the reproductive 
apparatus has escaped my attempts at detection: neither can I 
speak positively as to the exact position of the external orifices of 
generation. 
Embryology.—Some days after the capture of our little mol- 
lusk, I was much gratified at finding that it had deposited its 
spawn upon the sides of the glass jar in which it was confined. 
The spawn was laid in little spiral dises, Pl. VII. fig. 9, of four or 
