1903.] NATURAL SCIENCES OF PHILADELPHIA. 283 



four body whorls, measures only 8.5 mm. in extreme length. I have 

 collected a number of specimens of M. vickshurgensis at Vicksburg, and 

 feel sure that this is also distinct from staminea, having no suggestion 

 of the peculiar deep coarse revolving sculpture of that species. 



The Mitra 7nississippiensis of Conrad is a specimen of conquisita 

 in which the revolving lyration covers the entire body whorl; it is gen- 

 erally effaced on the upper parts of this whorl in half-grown and older 

 individuals, but occasionally persists until rather late in the growth of 

 the shell. Millingtoni is a different species . 



The Capulus occurring at Vicksburg is apparently different from 

 americanus of the Jacksonian, at least subspecifically. It is extremely 

 rare at Vicksburg and has been found thus far only in the upper marl . 



