196 BULLETIN OF THE 



outer lip. Aperture shaped as in muscorum, liaving a single small parietal denticle. 

 Altitude 3}, diameter I3 mm. 



Pupa syngenes, Tilsbry, The Nautilus, 1890, Vol. IIL p. 296, Plate V. Figs. 1, 2. 



Two specimens of this form are before me, and I am in doubt whether to give 

 them a new name, as tliey may be only sinistral monstrosities of the common 

 P. muscorum. The shells are labelled "Arizona" in the Academy collection, col- 

 lector not known. 



(Since tlio above paragraphs were in type, I have received a communication from 

 my friend, Dr. V. Sterki, to whom I sent a specimen of P. syngeties, which I at first 

 described as a variety of muscorum. He says : — 



" I am satisfied that it is a species, and not a var, of muscoruvi ; the shape of the 

 whole shell, tlie last whorl so considerably flattened, and ascending, the number of 

 wliorls, seem to me to prove its specifical rank. . . . After washing out tlie aper- 

 ture of your specimen, I saw a rather strong lamella or tooth on the columella, and 

 a barely perceptible trace of an inter-palatal lamella, which, however, is validified 

 by the impression on the outside.") 



The above is Pilsbry's description. An authentic specimen drawn by Dr. 

 Sterki is figured here. 



Vertigo ovata, Say. 



Of V. tridentata Sterki writes (The Nautibis, 1890, p. 1.35): "It has a 

 wide distribution in the northern part of the country ; originally found in 

 Illinois, it has been collected in different parts of Ohio and New York, as 

 well as in Minnesota and Colorado. In general it is remarkably constant in 

 its characters ; yet there are slight differences ; here I found a few examples 

 from low ground, together with V. ovata; they were a trifle larger, with a 

 thicker and deeper colored shell than those from upland places." 



