PART II. APLYSIAN^. 359 



SuB-FAM. 2. APLYSIANI^. Sea Hares. 



Mantle dilated, undulated at its edges and thrown 

 on the back ; branchia dorsal, pectinated, generally 

 covered with a convex, irregular, horny, or calcareous 

 plate ; tentacula two or four, ear-shaped. 



Aplysia Linn. Animal with a short neck ; tentacula 

 four, the upper and large pair flat, and folded so as 

 to resemble the ears of a hare ; mantle very large, 

 and sufficiently dilated for swimming, 

 fasciata. Rang. Ap. pi. 6, 7. Argus. Riipp. Atl. i. pi. 7. 



Thallepus Sw. Body more slender and fusiform ; 

 the lobes of the mantle short, and incapable of being 

 used for swimming ; tentacula two, large, ear-shaped ; 

 eyes not visible. 



T. ornatus Sw. Sp, Nov. See page 250. 



DoLABELLA Lam. Body pyriform, very broad behind ; 

 the lobes compactly folded on a hatched-shaped cal- 

 careous shell, which covers the branchia. 



D. Rumphii Lam. Blainv. Man. pi. 43. f. 5. 



BuRSATELLA BMuv. Body nearly globular; the dor- 

 sal edges of the mantle united together, but leaving 

 a short opening for the passage of the water to the 

 branchia, which have no covering. 



B. Leachii Blainv. Man. pi. 43. f. 6. 



NoTARCHUs Cuv. Body shaped much like that of Aply- 

 sia, covered with flat palmated lobes or membranes; 

 tentacula two, large and palmated ; mantle and 

 branchia as in Bursatella. 



N. laciniatus. Riipp. Atl. i, pi. 7. f. 2. 



SuB-FAM. 3. BULLING. The Bullas. 



Animal without apparent tentacula ; body oblong ; both 

 extremities obtuse ; eyes vertical, very minute ; bran- 

 chia dorsal, covered by a convolute shell, destitute of 



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