1 16 PKOCEEDINGS OF THE MALACOLOGICAT, SOCIETY. 



(piantity of sand-iirains, sponge spicules, a few small Crustacea, and 

 nuinerous large Foraminifera of the genus OrhicuUna. AVhether the 

 animal swallows these as part of its diet or merely to assist it in 

 triturating its vegetable and animal food I am unable to say, but one 

 thing is certain, that they do not pass entire tliroiigh the intestine, 

 since the pyloric orifice is far too small. I am inclined to think that 

 they serve both for nourishment and as triturators, and eventually 

 oven the calcareous shell may be absorbed, seeing that Fterocera 

 must need a large amount of lime for the formation of its shell 

 while growing. The intestine is very narrow ; it curves round the 

 anterior border of the liver and, passing- under the kidney, becomes 

 suddenly enlarged and passes into the rectum ; this latter runs round 

 the right border of the kidney and opens into the mantle chamber by 

 a small anal oi'ifice. 



The heart is large and gives rise to a long anterior, and a shorter 

 posterior, aorta. 



The kifhiey is well developed : it is composed of two well-marked 

 pectinate glandular masses and a large receptive cavity, opening 

 externally into the mantle chamber and internally into the pericardium. 

 This organ is the tirst part of the uterus of Quoy and Gaimard and 

 Kieferstein. 



The genital organs are simple, as in all Prosobranchs, a long testis 

 occupying the dorsal border of the coiled visceral mass, fi'om which 

 spring several coiled tubes that unite to foi'm a closely coiled vas 

 deferens. This latter increases in size, its walls become glandular, 

 and it finally enters a short straight tube with thick glandular walls, 

 that opens at the upper end of the mantle cavity ; from this aperture 

 an open groove extends down into the penis. 



The specimen figured by Cams as a male is really a female, being a 

 bad copy of Quoy and Gaimard's figures with this new interpretation: he 

 closes the opening of the oviduct and, covering in the pedal groove of 

 their specimen, places the genital aperture in the anterior division of 

 the foot. Quoy and Gaimard's figure of the female organs, with the 

 exception of the confusion between the kidney and uterus, compares 

 well with that given by Haller ' for Stromhus, including the curiously 

 branched uterus and the long ciliated groove leading from the genital 

 orifice down to the foot, the function of which it is difficult to 

 understand, unless it be concerned in oviposition. 



The nervous system is that of a typical streptoneurous form, and 

 consists of a nerve ring placed round the junction of the crop and 

 (esophagus, on which there are well-marked cerebral ganglia, supplying 

 the snout and eyes ; behind these a pair of pleural ganglia, and below 

 the oesophagus two pedal ganglia, the latter giving off numerous 

 pedal nerves, Avhile from the pleural ai'ise a pair of visceral nerves, 

 that springing from the right side, crosses over the crop, and ends in a 

 splanchnic ganglion on the left side, whence the nerve of the osphradium 

 originates, while the left nerve passes under the crop and supplies the 



' Ilallcr, Morph. Jalir. Bd. xix. 1893, pi. xix. fig. 17. 



