193 



Obs. This is a small species, and the slight irregularity in the 

 curvature of the lateral edge, exhibits the unequivocal characters 

 of this genus. PI. 38. 



BuLLiNA. — Shell cylindrical-oval, convolute, imperforate ; spire 

 elevated, short; aperture longitudinal, elongated, much narrowed 

 above; labrum simple, gradually much more prominent in the 

 middle than at the extremities, meeting the preceding volution 

 with a deeply re-entering angle ; at base widely and regularly 

 rounded ; columella with a slight fold. 



Obs. Blainville quotes Ferussac for this genus, which, perhaps 

 inadvertently, he calls Bulme, with one 1, instead ofBullinaas the 

 latter author writes the word. He has, however, considerably 

 limited the group by assigning to it the character of " fortement 

 involv^es, spire visible et saillante a I'exterieur ; I'overture tres 

 etroite en arriere," which excludes some of the species compre- 

 hended by Ferussac. He also places it as a subgenus under Bulla, 

 with " la Bulle, la Jonkaire," of Basterot, as its type. The ani- 

 mal differs from those of the genera Bulla, Scaphander and At^/s, 

 by having two distinct tentacula, and from Bullea by being in- 

 cluded within the shell. The shell differs by its prominent spire, 

 which in those genera, when it exists at all, is umbilicated. 



In its general form and habit it has much resemblance to Vol- 

 mirta, ; but the shells of that genus are emarginate at base. 



BuLLiNA CANALICULATA. — Volvaria canaliculata, nob. Jour. 

 Acad. Nat. Sc. vol. 6, p.. 211. 



Obs. This genus has been constructed subsequently to the pub- 

 lication of my description of the above species. 



In comparison with a fossil shell of Dax, sent to me by Mr. 

 Hoeninghaus of Crefeld under the name of B. lajonkeiriana, 

 Baster., before mentioned, it is a little larger, and evidently dif- 

 ferent in having the shoulder grooved ; whereas in that species the 

 .shoulder is acute and the suture is profoundly impressed. PI. 39. 



Gardita. — Shell equivalved, inequilateral, thick, suborbicular, 

 free, regular, ribbed, the margin crenate ; epidermis distinct ; hinge 

 of two teeth, one of which is short, direct, and the other oblique, 

 elongated in one valve, and in the other valve, is a large cardinal 

 recipient cavity with an oblique tooth on each side of it, nearly 

 parallel with the margin ; ligament subexterior ; two obvious mus- 

 cular impressions united by an arquated, entire palleal line. 



