THE NAUTILUS. 139 



Melainpiis flainis Gmel. Not common. 



Limncea hnmilis Say. Common in fresh water ponds on Anastasia 

 Island. 



Physa pom ilia Conr. Common with the above species. 



Physa heterostropha Say. Some young specimens evidently this 

 species, from Tocoi St. John's River. 



Planorbis tumidus Pfr. Common in ponds on Anastasia Island. 



Planorhis dilatatus GId. A few specimens near St. Mark's pond. 



Ancylus (Acroloxus) fihsus Conr. Common in a swamp near 

 Matanzas. 



Ancylus sp. f At Tocoi on the St. John's River. 



Siphonaria lineolata d'Orb. Common on the old light house rocks. 



HELIX HORTENSIS IN AMERICA. 



BY T. D. A. COCKERELL. 



There seems to be a prevalent opinion that this species does not 

 belong to America at all, but was introduced, like H. nemoralis. 

 This idea, however, is surely Avithout foundation, and Mr. AV. G. 

 Binney tells me that he regards the species as naturally present in 

 America. The distribution, though, is curious, and half suggests the 

 idea (which I believe is without reasonable foundation) that the 

 hardy Norsemen of old may have carried the snail about for food, 

 and so imported it where they went. At all events, it frequents the 

 places they visited. Starting with New England, the species goes 

 north to Canada, Labrador and Greenland. It appears also in 

 Iceland, and a small variety occurs in the Shetland Is., ^ and so we 

 come to the continent of Europe, where it abounds. 



H. hortensis is readily known from H. nemoralis, when ordinary 

 characters fail, by the shape of its " dart." It is also less variable 

 than nemoralis. I have examined specimens of the following 

 varieties, collected in America : — 



(1.) Helix hortensis var. vallotia Moq. 



There is an example of this variety from Labrador in the British 

 Museum. 



''■ The Slittland form was first named var. nana, but not described. It is now 

 known as var. minor Jeffreys. 



