THE 



AMERICAN NATURALIST 



Vol. XLIV October, 1910 No. 526 



VABIATIONS IN OTOSALPINX 

 DR. HERBERT EUGENE WALTER 



1. Introduction. — In a paper which appeared in 1898 

 Bumpus 1 showed that, in the case of Littorina littorea, 

 an introduced species shows more variability than the 

 same species in its original habitat. This Littorina was 

 recently so rare on the Atlantic coast that two pioneer 

 specimens were reported by Verrill from Woods Hole in 

 1875 while the first specimen found at New Haven was in 

 1880. Twenty years later it was probably the com- 

 monest mollusk to be found along the new England coast 

 and its range extended northward and southward con- 

 siderably beyond this area. Three lots of 1,000 each, 

 representing the former habitat of the species, were ob- 

 tained from the coasts of Wales, Scotland and England, 

 respectively, and these shells were measured so as to get 

 an index of their variability. Then ten 1,000-lots of the 

 introduced American shells were collected and measured 

 for comparison and it was found that nowhere in any of 

 the ten different localities, which extended from the St. 

 Croix Eiver in Maine to Newport, R. I., could shells be 

 found that did not have a greater index of variability 

 than did the British shells. Duncker 2 working over 



1 Bumpus, H. C, 1898, "The Variations and Mutations of the Intro- 

 duced Littorina," Zool. Bui, Vol. I, pp. 247-259. 



2 Duncker, G., 1S98, ' ' Benierkung zu deni Aufsatz von H. C. Bumpus: 

 The Variations and Mutations of tin- Introduced Littorina," Biol. Cen- 

 tralbl., Bd. 18, pp. 569-573. 



