THE NATURAL HISTORY SURVEY. 237 



"its upper end turning in nearly a right angle toward the ap- 

 erture, but not reaching the margin;" one on the base, small, 

 conical; three on the outer lip, as follows: one just above the 

 basal denticle, rather long, narrow, curved downwards; one in 

 the middle of the outer lip, short, conical; and the third near 

 the upper part of the lip, very small and conical; peristome 

 reflected, the terminations joined by a very thin callus; um- 

 bilicus small, open* (Fig. 67). 



Length, 1.75; diameter, 0.75; aperture length, 0.30 mill. (12322.) 



Animal: Not seen. 



Jaw: Not examined. 



Radula: Not examined. 



Genitalia : Unknown. 



Distribution: Ohio to Manitoba, New Mexico, Kansas. 

 (Sterki.) Put-in-Bay Island, Lake Erie. (Bryant Walker.) 



Fig. 67. 



BIFIDARIA HOLZINGERI Sterki. (After Binney, Bull. Mus. Comp. 

 Zool., Vol. XIX, No. 4, p. 194.) 



Geological distribution: Pleistocene; Loess. 



Habitat: Similar to that of B. contracta. 



Remarks: This species is closely related to both armifera 

 and contracta. Dr. Sterki says: "Our species ranges beside B. 

 armifera and B. contracta Say, standing nearer the latter. Yet 

 it is different from this species by the shape of the aperture, 

 the wanting callous connecting the margins on the body whorl, 

 by the longer crest behind the aperture, which in contracta dis- 

 appears in about the middle of the (height of the) whorl, and 

 by the wanting constriction, especially in the columellar wall, 

 not to speak of the size and shape of the whole shell. The 

 lamellae also show some marked differences, such as the pres- 

 ence of a high basal, the shorter columella not reaching the 



*See Sterki, The Nautilus, 1. c., and Binney, Third Supplement, Bull. Mus. Comp. Zool., 

 Harv. Coll., Vol. XIX, No. 4, p. 193, to which the writer is indebted for much assistance. 



