1901.] NATURAL, SCIENCES OF PHILADELPHIA. 477 



The clausilium (PI. XXVII, figs. 30, 31) is parallel-sided, 

 acuminate below, abruptly and deeply emarginate above on the 

 columellar side of the filament. 



Length 10, diam. 2 mm. 



This specimen agrees with von MollendorfFs description of C. 

 gracilispira in color and form, but differs in having fewer whorls, 

 9^ instead of 10-11, and in having two minute intermediate 

 palatal plica? instead of only one. Moreover, the lip is rather 

 broadly reflexed, not merely " breviter expansum." 



The reddish specimen (PL XXVII, figs. 32-34) is wider than 

 the green, with the space above the principal plica very convex 

 (fig. 34). Whorls 9^-. The aperture is less oblique than in the 

 green specimen, but otherwise similar; the oblique flattening of 

 the top of the superior lamella, and the notch in the peristome to 

 the right of it being well marked. Internally it is similar to the 

 green specimen except in the following respects: the spiral and 

 inferior lamella are longer, ascending almost past the ventral 

 position; and between the upper and lower palatal plicse there is 

 one very low, nodule-like callus or intermediate plica. 



Length 10, diam. 2.2 mm. 



This specimen agrees with von MollendorfFs description in 

 having an identical palatal armature. In color and general 

 appearance it is a good deal like C. aurantiaca var. Erberi Bttg. 

 I did not examine the clausilium. The rather peculiar form of 

 the superior lamella, in,a front view, is the same in the two speci- 

 mens; and when the intermediate palatal plicae are so reduced as 

 in these shells, I am disposed to believe that the differences above 

 recorded are not of specific value. 



It is obvious, however, that more material is needed to satisfac- 

 torily elucidate the characters of the species. 



Group of C. sublunellata. 



This group was defined by von Mollendorff in 1885. It is 

 characterized by the palatal armature, the species examined by 

 him having " below the principal plait, first an upper palatal, after 

 this a very short second one, and then a short, straight lunella, 

 which in some forms is somewhat obsolete, but always discernible." 



In my opinion the group should be enlarged to include species 

 which have below the principal plica or plait, one upper palatal 



