*16 University of Texas Bulletin 



Turritella austinensis, n. sp. 

 Plate IV, figures 3, 4 



Dimensions. Apical angle 18, sutural angle 11. 



Descriptions. Shell medium sized, tapering, whorls six 

 or more in number. Sides of whorls flat, suture not well 

 defined, height of whorls narrow in comparison with the 

 width. The whorls are ornamented with five nodular ribs 

 which are largest at the posterior side of the whorl and 

 decrease in size toward the anterior side. In front of the 

 anterior rib are two fine lines, sometimes one. The spaces 

 between the ribs are covered with lines of growth and on 

 the older whorls there is an intermediate fine line between 

 the ribs, but in the other whorls these intermediate lines 

 vary from one to three. 



Comparisons. This species varies from T. georgetown- 

 ensis in its dimensions, in the shape of the shell and whorls, 

 and in its markings. Our species resembles Turritella 

 manuanensis, Newton, from South Africa, 1 but the sutural 

 angles differ. The whorls of the South African species are 

 beveled inwards to the suture which is well defined. In ad- 

 dition to the five tuberculated ribs there are eight fine lines 

 between the suture and the anterior ribs behind which is 

 a fine beaded line. 



Number of specimens. 2. 



Occurrence. Georgetown limestone, Shoal Creek, Aus- 

 tin, Texas. 



Turritella simondsi, n. sp. 

 Plate III, figures 9, 10 



Dimensions. Apical angle 21, sutural angle 5. 



Description. Shell large, thick, turreted, sides of whorls 

 almost flat, suture well impressed, and posterior side of 

 whorls square-shouldered. Whorls twice as wide as high. 



1 Newton', R. B. Cretaceous Gastropoda and Pelecypoda from Zulu- 

 land. 



