THE NAUTILUS. 103 



men figured, but it is so different from the genuine obscurus, 

 that I have but little hesitancy in referring it to this species. 



As the Floridan form is a well-marked and distinct species, 

 it must be recognized and I take pleasure in associating with it 

 the name of Dr. Dall, who first called attention to its occur- 

 rence in Florida. 



( To be continued. ) 



A NEW SPECIES OF MITSA FROM CALIFORNIA. 



BY WM. HEALEY DALL. 



MITRA OECUTTI, new species. 



Shell small, white, mottled with yellow brown, with five 

 whorls of which the white smooth blunt nucleus comprises one; 

 suture distinct, whorls moderately convex; spiral sculpture of 

 (between the sutures four, on the last whorl about a dozen) 

 strong rounded close-set cords closely undulated behind the 

 periphery by numerous low narrow axial riblets with about 

 equal interspaces; the cords in front of the periphery are not 

 undulated, but extend to the end of the canal; there are also 

 very fine axial striae in the interspaces: aperture narrow, simple, 

 the pillar with two plaits, the canal hardly differentiated. 

 Height of shell 5.6; of last whorl 2.6; diameter 2.7 mm. U. S. 

 N. Mus. Cat. No. 334567. La Jolla, near San Diego, Cal. ; 

 C. R. Orcutt. 



CHANGES IN WESTERN MOLLUSC AN FAUNAS. 



BY JUNTOS HENDERSON. 



In 1889 Professor T. D. A. Cockerell (Jour. Conch., VI, 61) 

 reported the following species as obtained by Mr. Charles T. 

 Simpson in Lodgepole Creek, Northeastern Colorado: 



Lampsilis anodontoides (Lea). 



Lampsilis ventricosa (Barnes). 



Lampsilis luteola (Lam.). 



Anodonta grandis gigantea Lea. 



