142 THE NAUTILUS. 



Fossil, in pleistocene or possibly later deposits on the shore of 

 Bear Lake, Utah, collected by the Hayden Survey, in company with 

 Planorhis trivolvis Say (var.), Carinifex newberryi Lea, Lymneea 

 utahensls Call, and Fluminicola fusca Hald. There are about 200 

 valves in the lot, including one right and one left of rather small 

 juv. The specimens are in the collection of the A. N. S. P., No. 

 C2825. 



This Spheerium cannot be ranged under any of the described recent 

 species. Of about the same length with S. sulcatum Lam., the mus- 

 sel is of very different shape and appearance: much higher, much 

 more inequipartite, the beaks are much narrower and more promi- 

 nent; the shell and hinge are stronger. It resembles more some 

 forms of S. aureiim Pr, (resp. forms ranged under that species), but 

 is larger, more inequipartite and oblique. 



It is worthy of notice that in numerous specimens the hinges are 

 partially or wholly reversed, just as in most of our recent species of 

 this group, and the posterior cardinal tooth of the left valve is 

 wanting or rudimentary, in some specimens well enough preserved 

 to show such details. So far as can be seen from a few fresher, not 

 chalky, specimens, the color was whitish or reddish to grayish, and 

 the surface shining. 



The species is named in honor of Dr. H. A. Pilsbry, to whom I 

 am indebted for the opportunity of examining this fine lot of fossils. 



NOTES. 



Note on Pholadomya pacifica Dall. This species was first diag- 

 nosed in the Smithsonian Miscellaneous Collections, Quarterly Issue, 

 July, 1907, no. 1727, p. 172. The fuller description and account 

 which appeared in the March number of the Nautilus (1909) had 

 been prepared and sent to the editor in May, 1907, as the publica- 

 tion of my paper in the Quarterly was then indefinitely delayed. 

 As I saw no proofs of the Nautilus issue, this fact is not stated in 

 it, but I now make the correction. Since both notices were pre- 

 pared, another complete specimen in excellent condition was dis- 

 covered in the Albatross collection, but unfortunately, though fresh, 

 it did not contain the soft parts. The presence of a resilium was 

 confirmed. The localities of the two dredgings have been received. 



