HELIX. 57 



H. HAYDENII, Gabb. PI. 10, figs. 40, 41. 



Widely umbilicated, cretaceous, with rough incremental striae 

 and strong revolving cords or ridges, suture impressed ; whorls 

 5, regularly increasing, the last anterioily deflected. 



Diam. 18 mill. 



Weber Canon, Utah. 



When this species was described its resemblance to certain 

 Madeira helices was pointed out, and Pfeiffer has since referred 

 it to the Madeiran group Craspedaria. That it has the very 

 distinct features of that group is apparent ; \ r et suites of speci- 

 mens before me show so conclusively its connection with H. 

 strigosa, that I only continue to give it specific rank tempor- 

 arily for convenience's sake. 



H. ALTERNATA, Say. PL 10, figs. 43-48. 



Widely umbilicated, moderately solid, obliquely costulate, 

 yellowish or whitish, variegated above with chestnut macula- 

 tions ; whorls 6, flatly convex, a little tumid at the suture, the 

 last rather narrow, not descending, periphery rounded or very 

 obtusely snbangulated. Diam. 16-25 mill. 



Eastern, Middle and Southern region of the United States. 



This is H. scabra, Lam. ; H. radiata, Gniel. ? H. strong (/lodes, 

 Pfr. ; H. infecta, Parreyss. A unicolored yellowish variety is 

 of occasional occurrence ; Mr. Bland described a form compara- 

 tively smooth, with a somewhat shining, subtranslucent epider- 

 mis, as var. Fergusoni. I do not think it entitled to varietal 

 distinction. 



Yar. MORDAX, Shuttleworth. Figs. 47, 48. 



Sublenticular, carinated, widely umbilicated, thin, yellowish 

 corneous, with interrupted chestnut strigations, remotely flexu- 

 oseiy costate ; whorls 5?, flattened. Diam. 18 mill. 



Mountains of No. Carolina. 



This variation, insensibly connected with the parent form, 

 points in the direction of H. Cumber Ian dian a, but the evidence 

 for the inclusion of the last-named form is not so conclusive as 

 in the parallel variation of H. strigosa (which replaces alter nata 

 in the far West) into Haydenii. 



