BULLA. 1 5 



Formerly regarded as a single genus, this extensive, 

 though little-known family, even when dismembered by 

 the separation of the AplustridtB, the Cylichnidce, and 

 the Philinida, still offers important differences in the 

 structure of the animals of which it is composed. Thus 

 we may contrast the blind Akcra, with its elongated head, 

 its expanded foot-lobes, and its elastic shell, with the ses- 

 sile-eyed Bulla, with its broad cephalic buckler, its short 

 sub-quadrate foot, and its spotted, solid shell ; the amphibi- 

 ous Smaragdinella, with its square head, sessile eyes, free 

 foot-lobes, and glaucous ear-like shell, with the eye- 

 less Scaphander, with its fleshy, shapeless head-disk, and 

 solid, loosely-involute shell, or again with the Aplysiaform 

 Cryptophthalmus, with its eyes concealed under the free 

 lateral margins of the head, and with the ample foot-lobes 

 folded on the back, leaving a branchial aperture at the 

 hind part of the body. 



Genus BULLA, Klein. 



Eyes conspicuous, sessile on the middle of the frontal 

 disk. Mantle with the outer margin forming a thick, 

 fleshy lobe. Foot with the lateral lobes moderate, and 

 the hind part not extending beyond the shell. 



Shell convolute, ovate or sub-globose, smooth, mottled ; 

 spire involute, sunken, causing the apex to be tubular or 

 perforate ; aperture extending the entire length of the 

 body-whorl; inner lip simple; columella none; outer lip 

 acute. 



Syn. Bullus, Mont/. Ampulla, Auct. Cymbium, Latr., 

 not Klein. Bullea, Blainv. Bullearius, Ditm. Vesica, 

 Swains. 



