1909.] 



NATURAL SCIENCES OF PHILADELPHIA 



509 



low but distinct branch runs towards the outer termination of the Up 



This branch is brownish, like the callus 



it rests upon, hence might easily be 



overlooked. The outer lip-tooth is 



slightly emarginate at the top, and 



curves inward. The outer basal tooth 



is compressed and larger than the inner 



one, which is also somewhat compressed. 



Alt. 8, diam. 16 mm.; diam. of aper- 

 ture 7.9 mm.; whorls 6^. 



Description and figure from the type 

 specimen, No. 1,274 of the Binney and 

 Bland Collection, American Museum of 

 Natural History, New York. We owe 

 the opportunity of studying this speci- 

 men to the kindness of Dr. L. P. Gratacap. 



Some specimens from Miller Canyon 

 are identical in characters with the type 

 of levettei. It probably was collected in 

 that canyon. 



In Carr Canyon there is a similar 

 race having some differential characters. 

 Dr. Henry Skinner collected a series of 

 several hundred shells. They were 

 taken about midway of the canyon as 

 shown in the map. These shells vary 

 in size: 



Alt. 6, diam. 13 mm.; whorls 6\. 

 " 7 " 13 " " 6$. 



" 7.5 " 15 " diam. aperture 7 mm. ; whorls 6^. 



The last whorl is rather depressed and periphery is slightly angular 

 in front, these being the main differences from typical A. levettei. In 

 some specimens the shape of the aperture and of the parietal tooth is 

 exactly as in levettei, but most examples have the aperture smaller, 

 the lip-ends approaching somewhat more, and connected by the thick- 

 ened edge of the parietal callus. The parietal tooth almost always 

 is recurved at the axial end, and bears a more or less distinct recurrent 

 branch from the distal end, as in levettei. In some examples, however, 

 the parietal tooth is straight and there is no perceptible outer branch; 

 the upper margin of the lip descends more deeply on the parietal wall 

 than in the type of levettei. The young snails form a very thick lip- 

 callus at resting stages. 



Fig. s. A, 

 (Bland). 



hmunella levettei 



Type specimen. 



