PLATE 2. 



Fig. 1. Strophomenia agassizi. Section along line C of fig. 4, pi. 1. 



Fig. 2. Same along line B of fig. 4, pi. 1. 



Fig. 3. Same along line A of fig. 4, pi. 1 . 



Fig. 4. Section along line H of fig. 5, pi. 1. 



Fig. 5. Section along line D of fig. 4, pi. 1. 



Fig. 6. Section along line F of fig. 5, pi. 1. (One third reduced). 



Fig. 7. Same along line G of fig. 5, pi. 1. 



Fig. 8. SamealonglineEof fig. 5, pi. 1. X 360. 



Fig. 9. Nierstrassia fragile. Ventral fold. X 360. 



Fig. 10. Section through radula. X 555. 



