56 NEW UNIONID.E OF THE UNITED STATES AND NORTHERN MEXICO. 



small papilla3 on the inner edges. Anal opening small, apparently without papillae. 

 Super-anal oldening very small, rounded on the edges, far removed from the anal opening 

 and united below. Color of the mass probably whitish, but the longtime (15 years?) 

 the specimens have remained in alcohol, has destroyed the color of the papillae, 

 border, &c. 



Embryonic shell light brown, triangular, with hooks, very near in form to An. 

 Lewisii (nobis). 



Remarks. — A number of specimens of various ages were in the collection of Dr. 

 Berlandier. It is a species very distinct from any which I have seen. It is per- 

 haps nearest to Dunlapiana (nobis), but differs in the beaks and in being more 

 square, the dorsal and basal lines being nearly parallel. Some individuals are 

 beautifully green, while others are almost entirely yellow in the epidermis. The 

 beaks are remarkably flat and the undulations of the tips are very small and 

 delicate. It is with great pleasure I dedicate this interesting species to my friend 

 Prof Joseph Henry, Secretary of the Smithsonian Institution, who is always so 

 liberally disposed to promote a knowledge of the zoology of the country, through 

 the means placed in his hands in the admirable institution over which he presides. 



