35^ JOURNAL OF CONCHOLOGY. 



ON AGRIOLIMAX MONTANUS IN COLORADO. 



By T. D. a. COCKERELL. 



The group of Agriolimax, which is represented in Europe 

 by A. l(zvis and its aUies, and in America by A. aunpestris and 

 ■its alHes, is essentially the boreal group of slugs descended from 

 a type which occupied the far north when the continents were 

 united. The European and American groups are much alike in 

 general appearance, and even in their anatomy they do not 

 present any important differences, so that Jhering ( "Jahrbuch," 

 1885) has proposed to unite them under the one name of Icevis 

 •Miill. I think, however, that there is sufficient difference 

 between them to warrant their separation, though it may be 

 conceded that the three races of the United States, namely, 

 campestris of the eastern, montanus of the central, and occidentalis 

 of the Pacific region, are geographical forms of one species — the 

 campestris of Binney. 



Ingersoll (Report U.S. Geol. Surv., 1875) described two 

 species of slugs from Colorado, and remarked that they were 

 the only ones he met with in the state. 



Limax montanus Ing. — Bluish-gray, form stout, with bliint 

 posterior extremity, length exceeding one inch. (Grand 

 county). 



Limax castaneus Ing. — Small and slender, length less than 

 one inch, colour lively brown, with a darker spot on mantle; 

 head and tentacles black ; sole white. (Blue River Valley). 



These appear sufficiently distinct from the descriptions, 



but I regard them as synonymous. The mountain form of 



ca?npestris, referred by authors to montanus, is abundant in most 



parts of Colorado, including the Blue River Valley, and could 



not have been missed by Ingersoll, and must therefore be one 



of his species. Yet it is not bluish-gray (fnontanus), nor has it 



a white sole and black head and tentacles {castaneus), except in 



J.C., v., Oct., 1888, 



