346 EXPLANATION OF PLATES, XVII. 



FIGURE PAGE 



14,15. Pyrgopolon clava Lam. From Chen LI, . . . 245 



16. Ditrupa subulata Dh. From Deshayes, .... 241 



17. Ditrupa goreensis Cless. From Conch. Cab., . . . 241 



18. Spirodentaliura oceola Walcott. From P. U. S. N. M., . 246 



19. Ditrupa arietina Mull, much enlarged. From Chall. Rep., 241 



20. Ditrupa (?) abbreviata Dh. From Deshayes, . . .242 



PLATE 38 (Dentalium vulgare). 



1, 2. Ventral and lateral views of animal with the shell re- 

 moved, ......... vi 



3. Section of the shell, vi 



4. Gut, viewed ventrally, . . . . . . ' . vi 



5. Alimentary tract, dorsal view, . . . . . vi 



6. One of the captacula, much enlarged, . . . . vi 



7. Animal in feeding position, ...... vi 



(All figures of this plate from Lacaze-Duthiers). 



PLATE 39. 



1, 2, 3. Dentalium bednalli P. & S. Pilsbry, del, . . 248 



4. Cadulus anguidens M, & S. J. ofC., ix, . . . .253 



5. Dentalium multistriatum Dh. From Deshayes, . .251 



5. Dentalium rectius Cpr., teeth. Pilsbry, del., . . . vii 



6. Dentalium occidentale Sti raps. Teeth. From Bars, . vii 



7. 8, 9. Siphonodentalium lobatum Sowb. Teeth. From Sars. vii 



10. Entalina quinquangularis Fbs. Teeth. From Sars, . vii 



11. Cadulus propinquus Sars, teeth. From Sars, . . . vii 



12. Dentalium (Lobantale) duplex Defr. From Deshayes, xxxi 



PLATE 40 (Chcetoderma). 



1-4. C. nitidulum, nat. size; fig. 5, head end, enlarged; fig. 

 7, oral shield from in front ; fig. 8, posterior end from 

 above ; fig. 9, the same from the side ; fig. 10, diagram- 

 matic section of radula in its sack and tongue; fig. 11, 

 the tooth ; figs. 13-15, spicules, those on the left from the 

 anterior, on the right from the middle and posterior parts 

 of the body. After Wiren and others, . .287 



12, 16, 17. Chsetoderma militare, spicules ; fig. 18, animal, nat- 

 ural size. After Selenka, 



PLATE 41 (After Wiren). 



16. Chsetoderma productum, head ; figs. 17-19, Animal, natu- 

 ral size ; figs. 20-24, spicules ; fig. 25, fig. 26, caudal 

 sense organ, ....... 



27. Track of Ch. nitidulum. From Wiren, . 



28. Burrowing of Ch. nitidulum. From Wiren, . . 285 



