ZONITES. 165 



the last occupying scarcely one-half of the shell : spire slightly 

 raised : suture moderatel}' deep, puckered by the lines of 

 growth : mouth nearly round and not much interrupted by 

 the penultimate whorl : outer lip not very oblique : umbilicus 

 rather narrow, but deep, disclosing all the internal spire. 

 L. 0-075. B. 0-15. 



Var. margaritacea. Shell pearl-white and nearly trans- 

 parent. 



Habitat : Among dead leaves and moss in woods 

 throughout the greater part, if not the whole, of Great 

 Britain from the Moray Firth district to Cornwall, as 

 well as in Ireland, but more local and less common than 

 the last species. The variety is equally diffused. This 

 species is one of our upper tertiary fossils. Gerstfeldt, 

 as well as Middendorff, has recorded its occurrence in 

 East and West Siberia; and other writers have given 

 Scandinavian, German, French, and Swiss localities for 

 it. I found it in tolerable plenty at Alexisbad and else- 

 where in the Lower Harz and also near Lausanne. 



Its habits are almost subterranean, and in other re- 

 spects resemble those of Z. nitiduJus, with which it is 

 often found, and from which it differs in its much smaller 

 size, the delicate form and sculpture of its shell, and the 

 umbilicus not being so large in proportion. According 

 to L. PfeifFer, it is the Helix Hammonis of Strom, which 

 was found at Trondjhem and published in 1765; but 

 Miiller has referred it to Z. nitidus. Judging from the 

 description and figure given by Gould (in the ' Inverte- 

 brata of Massachusetts,^ p. 183, f. Ill) of his Helioc 

 electrina, I cannot agree with L. Pfeiffer in considering 

 that species identical with the present, either as regards 

 form or sculpture; and the habits of each species are 

 quite different. 



