THE NAUTILUS. 51 



ious races of the modesta-series by means of variations in the 

 number of teeth alone. It chances that the specimen chosen as 

 type is one of the 3-toothed forms. 



The animal is bluish-gray or slate in color, the body quite 

 dark, the foot and peripheral portions much lighter and semi- 

 transparent. A rough sketch of the cephalic region of one of 

 the Falls Creek specimens is offered in fig. 6. 



Whether the hereditary value of this race is that of a u form " 

 or a subspecies can only be shown by the more detailed study 

 which must be left for the future. Until then the personal 

 equation must necessarily largely govern. In any case it will 

 prove useful to have a name for it. 



VERTIGO ALLYNIANA new species. Fig. 7. 



The shell is minute, short, robust, ovate-conic in outline, 

 thin, dark reddish-brown in color, with only a dull gloss; 

 weakly, irregularly striate. The spire tapers with increasing 

 rapidity from the last whorl to the obtuse apex. The whorls 

 are convex, the last having a shallow but distinct excavation in 

 the palatal region and a weaker one over the upper palatal tooth, 

 the latter extending to the lip, which thus becomes flattened or 

 very slightly indented on its outer segment. The aperture is 

 pyriform in outline, and would be rather small except for the 

 quite flaring lip, which is little thickened and very fragile at 

 the edge. There are 5 teeth constantly developed in all the 

 material examined. The parietal, columellar, and upper and 

 lower palatal lamellae are well developed, and there is a distinct, 

 though small angular lamella. The columellar is situated well 

 back in the aperture and quite high up on the pillar. The 

 lower palatal is also rather deeply immersed. 



Length of type 2.1; diameter to lip edge 1.3; length of aper- 

 ture 0.81 mm.; whorls 4f. 



Type: Cat. No. 3764 of the writer's collection. Paratypes in 

 the Academy of Natural Sciences of Philadelphia, and the 

 private collection of Allyn G. Smith. 



Type Locality: Donner Lake, California; A. G. Smith, May 

 30, 1916; 22 specimens. 



Remarks : I am not quite certain of the relationships of this 



