48 SYSTEMATIC ARRANGEMENT 



* Operculum flat, with many spiral grooves. 



1. N. Canrena, t. 50. f. 2. 



2. N. hebrsea. 



** Operculum flat, with two or three marginal grooves. 



3. N. Marochiensis, t. 49. f. 3, t. 49. f. 4, t. 50. f. 4. 



4. N. maculosa, t. 122. f. 2. 



5. N. clausa. 



*** Operculum with a large convex ridge. 



6. N. fulminata. 



b. Neveritina. Shell subglobose, solid. Operculum large, horny, 

 simple. 



2. Nevertta. 



Shell depressed ; spire depressed ; mouth half-ovate ; inner lip 

 thickened, callous, with a central cross-groove. 



1. N. glaucina, t. 12. f. 12, t. 119. f. 5, t. 50. f. 1, 3, 6. 



2. N. glauca, t. 120. 



3. N. Chemnitzii, t. 122. f. 6 ; Adams, Gen. Moll. t. 22. f. 3. 



4. N. limbata, t. 118. f. 2. 



5. N. sordida, Forbes $- Hanley, B. M. t. P.P. f. 3. 

 b". N. plumbea, t. 49. f. 2. 



7. N. monilifera, Adams, Gen. Moll. Fig- 2%.— Neverita Alderi. 



t. 22. f. 2. 



8. N. Montagui, Forbes fy Hanley, 



B.M. t. P.P. f. 4. 



9. N. Alderi, Forbes fy Hanley, B. M. 



t. P.P. f. 5. 

 10. N. Canrena, Forbes fy Hanley, B. M. t. P.P. f. 6. 



The hinder part of the forehead of Neverita glaucina is elevated 

 on the shell so as to hide the very small sessile eyes, which are 

 situated at the base of the tentacula. — Joannis, Mag. Zool. Class, v. 

 t. 37. When the animal withdraws itself into the shell, it contracts 

 the foot, which emits a very large quantity of water from its gill- 

 cavities, or rather the aquiferous tubes. When the animal walks, it 

 moves the front part of its enlarged foot almost from side to side like 

 a feeler. 



Foot of Neverita castanea very large, roundish-elliptical, thick, 

 with very thin margins, rugose, with very large oblique undulated 

 rugae in its anterior half, its colour dull yellow. Head indistinct, 

 broad ; over the mouth a thin-edged rugose flap, having three 

 rounded crenatures, and continuous with the tentacula, which are 

 rather small, rugose, much depressed or flattened, and taper to a fine 

 point ; externally of the tentacula, on each side, a thin rounded lobe, 

 on which are placed in other species the eyes, of which, however, I 



