THE NAUTILUS. 103 
men figured, but it is so different from the genuine odscurus, 
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 MITRA FROM CALIFORNIA. 
BY WM. HEALEY DALL. 
MITRA ORCUTTI, 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 MOLLUSCAN FAUNAS. 
BY JUNIUS 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. 
