GIRTY, THE WEWOKA FORMATION OF OKLAHOMA 135 



scribed under the genus Limatulina, but as the genus was ascribed to 

 Wood instead of de Koninck, the group which I had in mind is apparent. 

 The form is clearly not a Limatulina and the proper title is Limatula 

 striaticostata. It differs from the species under consideration in being 

 much smaller, more oblique, and in having different surface ornamenta- 

 tion. 



Horizon and locality : Wewoka formation ; Wewoka quadrangle, Okla. 



Scaphopoda 



Dentalium semicostatum sp. nov. 



This type is represented by two fragments, which, so far as shown, indicate 

 a straight or gently curved, slowly enlarging conical shell. The cross section 

 is distinctly elliptical, having in the larger fragment a diameter of 7 mm. in 

 one direction and 6 mm. in the other. The test is thick and marked by rather 

 fine, rounded, wavy, longitudinal costa?, separated by linear stria?. These mark- 

 ings are confined to one side of the shell, and about four or five occur in 1 mm. 

 There are also transverse constrictions and incremental lines which have an 

 oblique direction to the axis. The obliquity of these markings is in the direc- 

 tion of the long axis of the section, so that their most distal points occur down 

 one of the narrow sides of the shell, and the most proximal down the other. 

 The costa? also are confined to one of the narrow sides, and they occur on that 

 on which the transverse striae are farthest from the apex. 



This shell is somewhat similar to D. mexicanum. It bas, however, 

 slightly finer costa? at a considerably larger size, and these are restricted 

 to one side of the shell. 



Horizon and locality: Wewoka formation; Wewoka quadrangle, Okla. 



Dentalium indianum sp. nov. 



Shell rather small, gradually tapering, very slightly curved. Section circu- 

 lar or obscurely elliptical. Surface marked by numerous thin, sharply ele- 

 vated, longitudinal costa? which are separated by intervals of about double 

 their own width. The number of costa? can not be counted with accuracy, but 

 it is not far from 42. There appear to be also fine, transverse, crenulating 

 stria?. 



This form stands nearest to D. mexicanum by reason of its numerous 

 fine costa?. These are, however, more numerous and are separated by 

 relatively wider intervals, while the shell itself is gently curved instead 

 of being straight, as in the western form. 



Horizon and locality : Wewoka formation ; Wewoka quadrangle, Okla. 



