338 BULLA. 



I cannot make this fit in with any previously known species. It 

 may prove not to be a typical Bulla. (Dall). 



B. CLAUSA Dall. Unfigured. 



Shell small, subtranslucent, solid, of the form of B. solida (Gmelin, 

 non Brugiere) pale yellowish-brown verging towards salmon color 

 in the darkest parts ; surface polished, with well marked incre- 

 mental lines and extremely fine microscopic wavy spiral striae over 

 the whole surface. Aperture as long as the shell ; wide anteriorly 

 with a strongly arched callus, white columella having a groove be- 

 hind it and a thin callus on the body. Apex impeforate, meeting 

 the descending outer lip with hardly a dimple. Max. Ion. 11/5; 

 Max. lat. 7-75 mill. (Dall). 



Bulla. clausa DALL, Blake Gastr., p. 57. 



Florida, collector unknown, U. S. Nat. Museum, JS"o. 55188. 



This is the only shell, except the abyssal species like eburnea and 

 abyssicola, having the solidity and characteristic form of typical 

 Bulla, which I have found without an apical perforation or distinct 

 pattern of coloration, yet it seems too heavy and porcellanous to be 

 referred to Haminea. It was probably collected by Stimpson. 

 (Dall). 



B. ABYSSICOLA Dall. PI. 36, fig. 31. 



Shell of moderate size, and nearly the shape of B. ampulla, but 

 proportionately wider behind, white with an ill-defined band of pale 

 yellow-brown encircling the periphery ; aperture as long as the 

 shell ; outer lip simple, nearly straight, rounded before and behind, 

 not extending beyond the summit of the left side of the shell ; apex 

 depressed, immersed, forming a slight pit with none of the whorls 

 visible ; surface ornamented with fine, minutely punctate spiral 

 grooves, more crowded before and behind, more distant about the 

 periphery, from four to twelve in the width of a millimeter and from 

 eight to ten punctations in the length of a millimeter, according to 

 the part of the shell examined, besides these there are numerous still 

 finer striae, also punctate, but more finely, which, when very faint, 

 appear like rows of very faint puncticulations; otherwise the sur- 

 face is smooth, or even polished, the lines of growth hardly per- 

 ceptible ; aperture narrow behind, wide in front, the pillar reflected, 

 and a thin layer of callus evenly spread over the body within the 

 aperture; proportions of younger specimens much the same, but a 



