96 H. J. FLEUCE. 



Fig. 5, ^. — Excretory and genital organs of the male of Tanganyikia 

 rufofilosa (after Moore). 



Fig. 6. — The same organs in Nassopsis nassa (after Moore). 



Fig. 7. — Male genital organs of Ty phobia horei (after Moore). 



Fig. 8, a. — Excretory and genital duct in Paludina vivipara — male. 



Fig. 8, b. — The same — female. 



Fig. 9, u. — The same — female of Littorina litorea. 



Fig. 0, h. — Section of the ha?matic gland (pericardial gland and renal gland) 

 of Littorina (after Perrier). 



Fig. 10. — Excretory and genital ducts, etc., in Buccinum undatum. 



Schematic Cross-Sectioks of Mantle Cavities. 

 Fig. 11.— Haliotis. 

 Fig. 12. — Acinoea. 

 Fig. 13.— Trochus. 

 Fig. H. — Littorina female. 

 Fig. 15. — Paludina female. 



In Figs. 5, 8, 9, a, and 10 it is supposed tiiat the roof of the pallial chamber 

 has been cut along near tiie middle line and reflcxcd. 



In Figs. 11 — 15 it is not suggested that the various apertures, etc., occur 

 in one and the same transverse section. 



