44 James E. Conkin, Barbara M. Conkin, William T. Mason, Jr. 



Table 11. Measurements of Helisoma tenue sinuosum in mm. 



Specimen 



Section 



and bed 



nos. 



Length 



Max. 



diam. 



Min. 

 diam. 



Apert. 

 height 



Apert. 

 width 



No. of 

 whorls 



7, PI. 2, figs. 2a-c , 

 8 



2,5 

 .... 2,5 



5.5 

 8.0 



10.2 

 15.1 



8.6 

 11.0 



5.2 

 7.0 



3.0 

 5.0 



4 

 4 









Physa sp. 

 PL 2, figs. 3a, 3b. 



Description. Shell has a thin callus which is reflected onto the body whorl; 

 body whorl is three-fourths of the total height of the shell; present specimen is 

 small. 



Measurements. Measurements for Physa sp. are given in Table 12. 



Distribution. Widespread. 



Ecology. "Physa is a genus of pond or small-stream snail, usually found in 

 quiet or stagnant water, but some species occur in swift, clear streams ... it 

 dates from the Cretaceous of North America" (Leonard, 1950, p. 21). 



Remarks. Present specimen probably represents an immature form. 



Table 12. Measurements of Physa sp. in 



mm. 







Section 

 and bed 

 Specimen nos. Length Diam. 



Apert. 

 height 



Apert. 

 width 



No. of 

 whorls 



77, PL 2, figs. 2a, b 2,5 3.5 1.9 



1.6 



0.8 



3 



Polygyra texasiana (Moricand) 

 PL 1, figs. 4a-c. 



Description. Specimens are in essential agreement with those of Pilsbry ( 1940, 

 p. 617). 



Measurements. Measurements for Polygyra texasiana are given in Table 13. 



Distribution. Polygyra texasiana is characteristically a southern species oc- 

 curring in Arkansas, Oklahoma, and Louisiana; in Texas, east, south, southwest, 

 and central (Pilsbry, 1940, p. 617). 



Ecology. "Polygyra texasiana lives in timbered areas, under leaves, logs, and 

 stones" (Leonard, 1950, p. 35). 



Remarks. Polygyra texasiana has been reported in the Yarmouthian and 

 Aftonian by Leonard (1950, p. 35). Conkin and Conkin (1962, p. 351) have 

 recorded the species from the Pliocene. 



Table 13. Measurements of Polygyra texasiana in mm. 



Section 



and bed Max. Min. Apert. Apert. No. of 



Specimen nos. Length diam. diam. height width whorls 



12 2,5 



13, PL 1, figs. 4a-c .... 2, 5 



14 2,5 



15 2,5 



16 2,5 



17 2,5 4.0 9.0 7.7 4.0 2.7 5*4 



5.9 



9.7 



8.0 



4.0 



3.0 



5*4 



4.5 



9.4 



8.0 



4.0 



2.8 



5 



5.1 



11.0 



9.0 



4.2 



3.0 



5i/ 2 



5.0 



9.9 



8.5 



4.0 



2.9 



5*4 



4.1 



9.5 



8.1 



4.0 



3.0 



5i4 



