172 LAND AND FRESH-WATER MOLLUSKS. 
the giants of the race in tropical Africa and 
America requires a good-sized basket to bring 
home only a few specimens. 
The animal of Achatina acicula is white and 
pellucid; the upper tentacles are long, but with- 
out eyes; the central tooth of the lingual ribbon 
is very small and pointed. The shell is very thin, 
slender, polished, and white, and, from its trans- 
parency, the dilatation and contraction of the 
respiratory cavity may be distinctly observed by 
the aid of a microscope, as irregular pulsations, 
reminding one of the action of the heart, for 
which it has been mistaken. 
This handsome species is recorded, in the ma- 
jority of local lists of land shells, as being found 
upon old walls or among the rejectamenta of 
rivers, but as dead shells; this appears to be 
accounted for by its subterranean habits, for its 
occurrence in a living state has been noticed 
when the soil or gravel has been overturned to a 
depth of some six or eight inches. 
That such is not its sole habitat, I have had 
opportunities of satisfactorily determining ; — 
thus, in many parts of the Cotswolds, this species 
has occurred to me in a living state, in bleak and 
dry situations, at an elevation of 500 to 1,000 
feet, under stones, among the turf of these cal- 
careous hills, or concealed deep in the fissures of 
the limestone rocks. I have even taken it among 
