THE NAUTILUS. 



VOL. XXVII. OCTOBER, 1913. No. 6 



FURTHER NOTES ON HELIX HORTENSIS IN NEW ENGLAND. 



BY CHARLES W. JOHNSON. 



About 1834 Amos Binney collected and later described (Boston 

 Journ. Nat. Hist., vol. i, p. 485, pi. 17, 1837) a form of Helix hor- 

 tensis as Helix subglobosa, stating that " it is common on the lower 

 part of Cape Cod and on Cape Ann, and is very abundant on Salt 

 Island, a rocky, uninhabited island near Gloucester." Salt Island 

 being the only exact locality mentioned might therefore be consid- 

 ered the type locality of this form. Binney had evidently at that 

 time not seen a banded form from North America, for on page 487, 

 in comparing these with the Helix hortensis of Europe, he says : 

 " Ours being yellow, with an olivaceous tint and destitute of bands, 

 while that is remarkable for its great diversity of coloring and 

 brilliant zones." 



Again referring to the species under Helix hortensis in his " Ter- 

 restrial Air-breathing Mollusks," vol. ii, p. 112, he says: "The 

 prevalent character of this and probably of other species in a given 

 locality seems to undergo a considerable change from time to time. 

 When I first visited Salt Island, where this species abounds, ten 

 years ago, it was impossible to find a single specimen with either 

 lines or bands, one uniform color prevailed throughout. At the 

 present time the banded varieties are said not to be uncommon." 



Recently I obtained from Salt Island a number of specimens, all 

 representing the plain olivaceous yellow form described by Binney 

 as H. subglobosa. Not a single banded form could be found on the 

 island. On the other hand, on Briar Neck, a rocky promontory only 



