Page:American Seashells (1954).djvu/359

Rh Fa7mly DIAPHANIDAE Genus Diaphiina Brown 1827 Diaphana minuta Brown Arctic Paper-bubble Figure 59b Arctic Seas to Connecticut. Europe. 3 to 5 mm. in length, globose, thin, fragile, and transparent-tan in color. Last whorl globose below, constricted somewhat above. Apex large, globose, obliquely and mammillarly projecting. Suture deep. Columella long, straight, not thickened, the edge partly closing the narrow umbilicus. Moderately common from 6 to 16 fathoms. Diaphana debilis Gould, D. hiemalis Cou- thouy and D. globosa Loven are considered synonyms of this species by Lemche (1948) and other modern workers. Family BULLIDAE Genus Bulla Linne 1758 The names Vesica Swainson 1840 and Bullaria Rafinesque 18 15 have been ill-advisably used for this genus. Fortunately, the name Bulla has been conserved for this group of bubble-shells by the International Commission for Zoological Nomenclature. Bulla striata Bruguiere Striate Bubble Plate 13P West coast of Florida to Texas and the West Indies. % to I inch in length, similar to occidentalis, but larger, heavier, and with the spiral grooves well-marked toward the base of the shell and within the apical perforation. The whorls are compressed at the apical end. Colu- mella usually with a brown-stained callus. Locally common. B. amygdala Brug. is probably a smooth form of this species. Bulla occidentalis A. Adams Common West Indian Bubble Plate 26p North Carolina to southeast Florida and the West Indies. V2 to I inch in length, smooth, varying from fragile to quite strong, and from cylindrical (young) to fairly swollen. Apex deeply and narrowly perforate. Color very variable, but usually whitish with mottlings, zebra stripes and obscure bands of brown. Surface with numerous, microscopic striations. This is a very common bubble-shell which is found most easily at night and at low tide on grassy, mud flats. The author is often misnamed as "C. B. Adams."