110 GASTEROPODA. 



Genus 6.— DOLABELLA — Lamarck. 



Generic Character Body creeping, oblong, narrowed in 



front, posteriorly widened, and there truncated obliquely by 

 an orbicular inclined plane; the margins folded over the 

 back; four somewhat tubular tentacula, disposed in pairs; 

 branchial operculum enclosing a shell ; anal orifice situated 

 on the back, near the branchiae, in the middle of the orbicu- 

 lar disk. Shell oblong, slightly arcuated, thicker, callous, 

 and somewhat spiral, on one side. 



Dolabella i?Mwip/aV.— Rumphius's Dolabella. Plate 



XIII. fig. 30. Base thick, callous, and subspiral ; dilated 

 above, thin, and wedge-shaped. Inhabits the Indian ocean, 

 the Isle of France. 



Genus 7 LAPLYSIA— Xmra^ws. 



Generic Character Body creeping, oblong, convex 



above ; bordered on each side by a broad mantle, which 

 covers the back when the animal is quiescent; head and 

 neck elevated; with four tentacula, of which the two upper 

 ones are ear-shaped ; the eyes situated near the mouth 

 before the ear-shaped tentacula ; the dorsal shield semi- 

 circular, sub-cartilaginous, adhering on one side, and cover- 

 ing the branchial cavity ; anal orifice placed behind the 

 branchiae. 



Laplysia radiata — The Radiated Laplysia. Plate 



XIV. fig. 25. Nearly round, left margin somewhat re- 

 flected ; outer lip acute ; yellowish horn-coloured, with 

 brown radiations, and two concentric bands. 



TRIBE III. BULLACEA. 



The branchiae situated in a particular cavity, near the 

 posterior region of the back, and covered by the mantle ; 

 no tentacula. 



