THE GASTROPOD GENUS VVANIA 31 



The columdlar lip is somewhat thickened and recurved upon itself. It 

 extends over and partially hides the shallow umbilicus. There is no thick- 

 ening or callosity developed upon the inner lip. 



The slit hand is situated along the outer margin of the upper flattened 

 portion o\ the whorl and occupies slightly less than one third the width of 

 thi> surface. It is hounded by two prominent costae whose converging slopes 

 meet about one fourth of the way below the upper costa and thus produce 

 the asymmetrically concave hand. No markings of any kind have been ob- 

 served upon the band. 



A prominent costa occurs upon the upper flattened surface of the whorl 

 adjacent to the suture hut separated from it by a space equal to about half 

 the width of the slit hand. This costa is about as prominent as the one 

 hounding the inner side of the hand. Upon the final whorls a second costa 

 somewhat finer than the first occurs below the first and is separated from 

 it by a space equal in width to that between the first costa and the suture. 

 The space between the costa upon the inner edge of the hand and the lower 

 of the two costae descrihed above is about as wide as or slightly wider than 

 the slit band and resemhles the hand in general appearance except that it is 

 somewhat flatter. No growth lines have lx?en ohserved upon this portion of 

 the shell. 



The lateral slope of the whorl below the outer edge of the slit band is 

 somewhat narrower than the upper slope. It is bounded below by a prom- 

 inent keel which hears upon its crest two costae of about equal development 

 although the lower projects beyond the upper. Together the costae are some- 

 what narrower than the slit band but the space between them does not re- 

 semble the hand as it is much narrower and relatively more concave- A 

 smooth concave surface separates these costae from the upper angle of the 

 whorl and makes up about three fourths of the lateral surface. The surface 

 is usually somewhat asymmetrically concave, the steepest part being in its 

 lower portion. Xo lines of growth have been ohserved upon this portion of 

 the shell. 



The basal surface of the whorl hears two or three costae on its outer 

 portion. The outermost of these is the most prominent, hut is somewhat less 

 conspicuous than the costae on the lower part of the lateral slope. The second 

 costa of the base is slightly less developed than the first, and the third where 

 present is very fine and thread-like. The first costa of the hasc is separated 

 from the edge by a space slightly wider than that which separates the two 



e of the lateral surface. The space between the first and second costae 

 of the base may he about equal to or slightly greater than the space between 

 the first and the cch^v of the basal surface. The space between the second 

 and third costae where the latter is developed is considerably greater. The 

 central part of the basal surface is without ornamentation but fine costae 



