THE TANGANYIKA PROBLEM. 



243 



The otocysts lie behind the pedal ganglia, and the 

 otocyst nerves pass directly behind the cerebro-pedal and 

 pleuro-pedal connectives to the cerebral ganglia on each 

 side. The otocysts are not large, and are round, as 

 distinguished from those of Nassopsis. The otoliths are 

 small, rectangular or barrel-shaped, and numerous. 



The reproductive apparatus is very simple, and in both 

 sexes consists of a genital gland which occupies the upper 

 surface of the two last whorls of the animal's body. This 



Fig. 25. — Lingual dentition of Paramelania aamoiii. 



gland is put in connection with a large non-convoluted 

 oviduct or vas deferens, as the case may be, by a number 

 of fine tubes ; and both ducts pass beneath the intestine 

 and open just behind the anus in a large slit. 



The genital duct in both sexes is much enlarged within 

 the mantle cavity, somewhat in the manner of the same 

 structure in the genus Typhobia. But in Bythoceras it is 

 quite destitute of the singular organ which I described as 

 an evertible penis in the male Typhobia* 



* "Quart. Journ. Micr. Sci.," Vol. 41, 1898, p. 191, loc. cit. 



16* 



