360 BULLID, 
concave, umbilicated; aperture as long as the shell; inner 
margin without columella; outer lip trenchant. 
Teeth, central one, laterals numerous, uniform, in an arched 
series. Animal partly investing, but not entirely covering the 
shell. Hyes conspicuous, sessile on the middle of the frontal 
disk. Mantie with the outer margin forming a thick, fleshy 
lobe. Foot with the lateral lobes moderate, and the hind-part 
not extending beyond the shell. The species of this genus 
inhabit sandy mud-flats, the slimy banks of river-mouths, and 
brackish places near the sea; at low-water some of them conceal 
themselves in the mud and under sea-weed, exuding large quan- 
tities of mucus to maintain the moisture of their skin; they 
feed on bivalves and other mollusca, which they swallow whole, 
reducing and crushing them afterwards by the calcareous plates 
of their powerful gizzard. The shells of Bulla, as restricted, are 
rather solid, smooth, and mottled and marbled like birds’ eggs. 
HamineEA, Leach. 
Hxample.—H. hydatis, Linn. (1xxxvii, 37, 38). 
Shell oval-globular, spiral, ventricose, corneous, thin, covered 
by a slight, smooth epidermis ; spire involute. May be distin- 
guished from Bulla immediately by the want of color in the shell. 
Atys, Montfort. 
Hxample.—A. naucum, Linn. 'Ixxxvii, 39). 
Shell rather solid, uncolored, with a smooth epidermis ; 
usually spirally striated ; spire scarcely visible; aperture longer 
than the inner margin at both ends; columella with a single, 
more or less obsolete plication. ; 
The animal is blind, or the eyes are subcutaneous. 
LAONA, A. Ad. Semiovate, thin, striz of growth. lamellar, 
spire hidden; aperture with the inner lip arcuated, outer lip 
simple. A. zonata, A. Ad.» Japan. 
pinta, H. and A. Adams. Shell ovoid; subtruneated behind, 
longitudinally striated; inner lip truncated: anteriorly, termi- 
nating in a tooth-like projection. A.dentifera, Ad. (1xxxvii, 40). 
sao, H. and A. Adams. Shell pyriform, ventricose in front ; 
umbilicated ; apex involute; aperture narrow behind, wide in 
front; columellar lip reflected ; outer Jip thih, sinuous. A.pyri- 
formis (Ixxxvii, 41). 
PHYSEMA, H. and A. Adams. Shell small, thin, hyaline, glob- 
ular; umbilicated ; very finely longitudinally striated ; columella 
a little arcuated, reflected; outer lip thin, free behind, developed 
in the middle. A. hiemalis, Couth. (Ixxxvii, 42). 
ROXANIA, Leach. | Shell ovoid, solid, perforate, decussately 
striate, transversely profoundly suleate, the suleations strongly 
punctate; aperture narrow, dilated in front: inner lip sharp, 
