36 



obvious and characteristic assemblages of shells as refer to the genera in 

 question, though differing in no other respect, are equally entitled to generic 

 distinction. A system of arrangement based upon the characters of the 

 soft parts of the moUusk alone, without reference to the shell or hard parts, 

 is scarcely less objectionable than one founded upon the shell alone, without 

 reference to the organic structure of the animal. 



The shell of Ovulimi differs from that of Cyprtca in having the extremities 

 more or less prolonged, and in the lip and columella being destitute of the 

 prominent rows of teeth "wdth which that genus is so remarkably charac- 

 terized ; the outer lip, as in the 0. ovum and imj)erialis is in one or two in- 

 stances a little wrinkled, but never toothed. Another distinction consists in 

 the OvuUmi not being provided with any pattern or desigii of colour, nor with 

 colour in any form beyond a faint tinge of pink, violet, or yellow. 



The genus Ovulum is somewhat limited in species, and they are mostly 

 small ; the 0. ovum is the only one of large size, and the 0. imjpenalis the 

 only species of intermediate size ; the well-known Chinese species, the 0. 

 volva, presents a remarkable example of prolongation of the extremities, and 

 the 0. verrucosa, the nearest approach to Cyj^raa, is characterized by the 

 presence of two small wart-Hke callosities like those of the C. hicallosa. 



1. aciciilare, Sow. 



2. Adriaticum, Sow. 



3. aequale, Sow. 



4. album, Bufo. 



5. avena, Soio. 



6. birostre, Lam. 



7. breve, Sow. 



8. carneum, Lam. 



9. corrugatum. Hinds. 



10. dorsiiosum. Hinds. 



11. emargiiiatum, Soto. 

 13. formicarium, Soiv. 



Species. 



13. frumentum, Soto. 



14. gaUinaceum. Hinds. 



15. gibbosum, Lam. 



16. liordeaccum, Lam. 



17. inflexum. Sow. 



18. intermedium, Sow. 



19. lacteum, Lam. 



20. longirostratum, So7C. 



21. margarita, Soto. 



22. marginatum, Soto. 



23. iiigermum, Bufo. 



24. obtusum, Soto. 



25. ovum, Soto. 



26. patulum, Soto. 



27. pyriforme, Soto. 



28. rufiim. Sow. 



29. sccale, Soto. 



30. scminiihim, Soto. 



31. sjjelta. Lam. 



32. striatuliun, Sotc. 



33. tortile, Bes. 



34. triticeum, Lam. 



35. verrucosa, Soto. 



36. volva, La7)i. 



Figures. 



OvTJLTJM oruM. Plate F. — Fig. 3. Shell with animal, showing the ex- 

 panded disc, in slight folds ; the right lobe of the mantle with its 

 spinous processes partially extended ; the broad wrinkled siphonal ap- 

 pendage ; the tentacles proceeding from the concealed head ; and the 

 eyes on the thickened part of the tentacles. From the Zoologij of the 

 Voyage de V Astrolabe. 



Ovulum volva. Plate 1. Fig. 5.— Shell. From Mr. Cmning's collection. 



