I^otes on Certain Terrestrial MoUusks. 76 



The first impression given by the jaw is that it bears narrow, separated 

 ribs, as in BiiUmulus, CyUndrella, etc. A more careful study of it, however, 

 shows the ribs to be very broad, crowded, flat, with narrow interstices 

 between them. 



Lingual membrane with 17-1-17 teeth; six laterals. Centrals (fig. 2, B) 

 with the base of attachment longer than wide, the lower lateral angles 

 expanded; upper margin broadly refiected; reflection very short, tricus- 

 pid, side cusps decidedly developed, short, bearing distinct cutting 

 points, median cusp long, slender, bulging at sides, reaching nearly to 

 the lower edge of the base of attachment, beyond which projects slightly 

 the distinct, long cutting point. Laterals like the centrals, but unsymmet- 

 rical by the suppression of the inner, lower angle of the base of attach- 

 ment, and inner side cusp and cutting point. Marginals (flg. 2, C) acule- 

 ate, their base of attachment less sole-like than usual in Zonites, but more 

 circular in outline. Eig. C shows these bases of attachment. Fig. D 

 gives one marginal tooth in profile. 



This is the first known instance of a species with ribs on 

 its jaw having aculeate marginal teeth ; or of a species fur- 

 nished with a Zonites-like shell having decided ribs on its 

 jaw. It will be difficult to find a place for the species under 

 any description of genus or subfamily. The shell is that of 

 Zonites^ but that genus has a ribless jaw with median pro- 

 jection. 



Zonites Stearnsii, nov. sp.? 



With land shells from the west coast, kindly sent to me 

 for examination by my friend Mr. Stearns, I lately noticed a 

 single specimen of a form from Astoria, Oregon, allied to 

 Z. Lansingi. It is larger, more elevated and more distinctly 

 striated than that species, has seven whorls, with rather wider 

 and more rounded aperture, but without the lamella within 

 the outer margin of the peristome. 



Tlie measurements are diam. maj., 4, rain. 3 J mill., alt. 

 2i mill. 



Having before me a single specimen I am unwilling for- 

 mally to describe the species, which for the present I desig- 

 nate as Zonites Stearnsii. 



