298 HELICID^. 



the pellucid sliell : mouth oblong, contracted by the penultimate 

 whorl, narrowing above into an acute angle, slightly widened 

 and rounded below, but interrupted by a deej) notch at the 

 base of the pillar lip : outer lip thin and flexuous : pillar lip 

 thick and curved : inner lip consisting of a slight deposit of 

 shelly matter, which is spread on the pillar. L. 0"175. 

 B. 0-04. 



Habitat : Under stones and at the roots of bushes 

 and gi^ass, but usually some inches beneath the surface, 

 in various parts of the country from Yorkshire to Guern- 

 sey, as well as in Wales and Ireland. It occurs in our 

 upper tertiary strata. On the Continent it ranges from 

 Sweden to the South of Italy; and it has been also 

 noticed in Greece, Algeria, and Madeira. It is widely 

 diffused, but rather local, and difficult to find in a living 

 state. 



Nilsson has given a good description of this curious 

 little mollusk, and has noticed that, in consequence of 

 the transparency of the shell, the irregular motion of its 

 breathing could be easily observed under a microscope, 

 and that, when the respiratory cavity was shut, the 

 motion ceased, but was resumed on the chamber being 

 again opened ; and he likened this alternate expansion 

 and contraction of the breathing- organ in this snail to the 

 pulmonary action of vertebrate animals. He supposed 

 that the A. acicula fed on the tender and juicy fibrils of 

 the roots of grass. Mr. Pickering informed me that a 

 considerable number of live specimens were once pro- 

 cured by a gentleman in Hertfordshire, while digging up 

 potatoes. His friend, not being a conchologist, thought 

 at first that they were little white maggots. It has been 

 stated that this species is only fomid in calcareous soils • 

 but, besides the last instance, its occurrence has been 

 noticed by Mr. Bridgman at Norwich, "on a sunny 

 bank near the Thorpe toll-bar, adhering to the roots of 



