184 J. E. S. MOORE. 



Fig. 11. — The pericardial cavity and iieart of rufofilosa. 



Fig. 12. — Rudimentary spermatic groove in the male Melania epis- 

 copalis. 



Fig. 13. — Dissection of the female Melania episcopalis, showing the 

 relations of the super-oesophageal brood-pouch. A bristle is passed through 

 the opening of the brood-pouch, x., into its interior cavity. 



Fig. 14. — The mantle cavity of a female Tanganyikia rufofilosa, 

 shovping brood-pouch containing embryos similar to that in Melania epis- 

 copalis (see previous figure), but subcesophageal and on the left side. 



PLATE 15. 



Fig. 1. — Partial dissection of Littorina litteria. 



Fig. 2. — Posterior portion of the mantle cavity of a Faunus species (?). 



Fig. '6. — Nervous system of Melania episcopalis. 



Fig. 4. — Nervous system and radular sac of Melania aspirata. 



Fig. 5. — Nervous system of Melania (?). 



Fig. 6. — Nervous system of Tanganyikia rufofilosa. 



Fig. 7. — Melania aspirata, showing gills and genital groove. 



Fig. 8. — Buccal mass, cerebral ganglia, and radular sac of Melania 

 episcopalis. 



Figs, 9 and 10. — Gills and radular sac of Faunus species (?). 



Fig. 11. — Lower portion of mantle cavity of Faunus, showing flab-like 

 covering of the internal genital groove, ini. g. g., and the external genital 

 groove, g. v. 



Fig. 1 2. — Nervous ay stem o f L i 1 1 o r i u a litteria. 



Fig. 13. — Mantle organ of the Melanias, species (?). 



Fig. 14. — A single row of teeth in the radula of Melania episcopalis. 



Fig. 15. — Male Littorina litteria, showing the rudimentary spermatic 

 groove, g. v. 



PLATE 16. 



Fig. 1.— Semi-diagrammatic view of the reproductive apparatus in the female 

 Tanganyikia rufofilosa, showing the relation of the external genital 

 groove, g.v., to the internal subcesophageal brood-pouch, B.p. 



Fig. 2. — Similar view of («.) the female Melania episcopalis; (A.) re- 

 productive apparatus of the male. 



Fig. 3. — Semi-diagrammatic view of the reproductive apparatus in a male 

 Strombus, showing the relation of the spermatic groove to the permanent 

 penis. 



