228 



THE TANGANYIKA PROBLEM. 



female that portion of the genital duct which lies within 

 the mantle cavity is dilated so as to form a large broad 

 pouch, in which the ova go through their later stages of 

 development. (Fig. 5). 



BATHANALIA, MOORE. B. HOWESII (FIG. 8). 



The remarkable form to which I gave the name Batha- 

 nalia howesii is also an inhabitant of the deep water of 



Fig. 10. — A single row of the lingual teeth of Bathanalia howesii. 



Tanganyika throughout the southern third of the lake. It 

 is characterised chiefly by its shell which, in all essential 

 conchological characters, is identical with several marine 

 Jurassic fossils that have been described under the name 

 Amberleya. Except for its widely different shell, Batha- 

 nalia is structurally identical with Ty phobia, even the 

 lingual teeth presenting only the minor differences seen 

 on comparing Figs. 4 and 10. 



CHYTRA, MOORE. CHYTRA KIRKII (FIG. I I ). 



The anatomy of this remarkable form was worked out 



