152 Prof. G. J. Allman on the Anatomy 0/ Actseon. 



seen to enter close to one another. One of these tubes, s, runs 

 a little forwards, then bends backwards and bifurcates, the divi- 

 sions again bifurcating dichotomously : its ultimate distribution, 

 however, I have not succeeded in tracing. The other tube, /8, 

 runs forwards to the oval body, x, 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, 7. 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, 00, and backwards 

 through the bifurcating tube, z. With the plicated body, 7, 

 which I would feel inclined to look upon as a testis, a pyriform 

 sac, 8, 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 terminates 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, f f f. 

 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 entii'e length with closely-set 

 sacciform appendages, PI. VII. fig. 8 a. These contain a gi'anular 

 substance, but whether they communicate with the interior of the 

 tube is not very manifest. Besides these appendages, numerous 

 spherical capsules, PI. VI. 6 6, and PI. VII. fig. 8 b, 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, PI. VII. fig. 8 e e, 

 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 discs, PI. VII. fig. 9, of four or 



