varieties of form and colour. The shell, where it exists, is a horny, slightly 

 concave shield, attenuated and a little beaked at the hinder extremity. 

 In colour it is mostly of a reddish-fawn, passing into brown. In the fol- 

 lowing list of species there are probably many in which there is no rudi- 

 ment of a shell, but I have not sufficient data for separating them. 



1. alba, Cuv. 



2. Brasiliana, Rang. 



3. Brongniarti, Bl. 



4. Brugnatelli, Vaub. 



5. camelus, Cuv. 



6. concava, Sow. 



7. dactylomella, Rang. 



8. depilans, Linn. 



9. fasciata, Poir. 



10. Ferussaci, Rang. 



11. fimbriata, Ad. 



12. fusca, Til. 



13. gelatinosa, Rang. 



14. Inca, D'Orb. 



Species. 



15. Keraudrenii, Rang. 



16. Lessonii, id. 



17. lineolata, Ad. 



18. livida, D'Orb. 



19. longicornis, Rang. 



20. maculata, id. 



21. marginata, Bl. 



22. marmorata, id. 



23. Neapolitan a, Ch. 



24. nigra, D'Orb. 



25. nodifera, Ad. 



26. oculifera, id. 



27. Petersoni, Sow. 



28. Poliana, Ch. 



29. protea, Rang. 



30. punctata, Cuv. 



31. quadrata, Sow. 



32. Kangiana, D'Orb. 



33. rosea, Rathke. 



34. sorex, Rang. 



35. tigvina, id. 



36. unicolor, Bl. 



37. virescens, Risso. 



38. viridis, Bosc. 



39. vulgaris, i?£. 



40. Webbh, Vaub. 



Genus 2. DOLABELLA. 



Animal; similar to that of Aplysia, with the branchial cavity 



more in the rear. 

 Shell ; calcareous or inclined to horny, hatchet-shaped, posteriorly 



somewhat thicker and a little reflected at the edye. 



The Bolabella is very like Aplysia in general aspect, and has its fore- 

 most tentacles developed in a similar manner, like expanded ears ; the 

 branchial cavity is, however, situated more towards the hinder part of the 

 animal, and the shell is larger, stouter, and more calcareous. 



The drawing of D. Rumphii, with its numerous filamentary processes, 

 given in our Plate L, was made by Mr. Arthur Adams from a number 

 which he observed at the Mauritius, feeding in groups of eight or nine in 

 a small muddy inlet of the sea. 



1. ascifera, Fir 



Species. 

 2. dolabrifera, Cuv. 



3. ecaudata, Rang. 



