168 Trans. Acad. Sci. of St. Louis. 



sculpture, having the aperture oblique, narrowly oval, nearly 

 half as long as the shell and completely undifferentiated from 

 the extremely short canal. The anal sinus is small but distinct 

 and abruptly formed ; it is but slightly everted from the axial 

 line of the aperture, though separated from the suture by a 

 thickened callus. The outer lip is not dilated and is non- 

 plicate. Columella with about two;broadly tumid oblique and 

 approximate folds at the middle. The spire is half as long as 

 the shell, with its outline even in profile from whorl to whorl, 

 and without break due to individual convexity of the whorls, 

 the side profile of each whorl very feebly arcuate, the sutural 

 breaks in the curve of profile narrow ; each whorl with about 

 three very broad approximate spiral lyrae, forming moderately 

 elevated tubercles or nodules on the numerous approximate 

 ribs; pillar not differentiated, the base of the shell obcouic. 

 The embryo is smooth, of between one and two whorls, very 

 broadly and obliquely obtuse at apex in profile, the summit 

 concave, the nucleus extremely small. Body whorls three to 

 four in number. The two species in my cabinet are the 

 following: — 



Shell white, variegated irregularly with dark brown; longitudinal ribs 

 separated by much less than their own widths and very numerous, 

 some twenty in number. Length, 4.0 mm.; width, 1.6 mm. 



mnltigranosa Smith 



Shell still smaller, clear and pale straw color throughout, the ribs separated 



by fully their own widths and about fifteen in number, much more nearly 



obliterated between the strong spirals than the latter are between the 



ribs. Length of a specimen of 3 body whorls, 2.9 mm.; width, 1.3 mm. 



insoleus n. sp. 



The general outline of the shell in this genus is not unre- 

 mindful of Mitromoiyha, but it differs in having a distinct 

 anal sinus. Probably many other species will be discovered, 

 hitherto overlooked because of their minute size. 



Taeanini. 



This tribe, though very limited in scope, is altogether iso- 

 lated and differs from the preceding not only in facies, but 

 in some important structural features, the most important 



