Pleistocene Snails from San Patricio County, Texas 39 



Table 2. Measurements of Armigerus obstructus in mm. 



Specimen 





Section 



.iiul hid 

 nos. 



Length 



Max. 

 diam. 



Min. 



ilium. 



Apert. 

 height 



Apert. 

 width 



No. of 

 whorls 



76, PL 2, figs, la 



, b .. 



.. 2,5 



1.1 



3.0 



2.6 



1.0 



1.1 



2>/ 2 



Bulimulus alternatus mariae (Albers) 

 PI. 2, fig. 7. 



Description. Length and diameter agree with Pilbry's forms (1946, p. 14); 

 however, apertures of our specimens are smaller; single blunt tooth distinctly out- 

 lined; several specimens retain their ragged gray stripes. 



Measurements. Measurements of Bulimulus alternatus mariae are. given in 

 Table 3. 



Distribution. This species is very commonly found in southwest Texas, and 

 in northern Mexico in the states of Tamaulipas, Nuevo Leon, and San Luis Potosi 

 (Pilsbry, 1946, p. 14). 



Ecology. "This species [Bulimulus alternatus mariae] .... often occurs in 

 great abundance, and sometimes, in aestivation, may be seen sealed to large cac- 

 tus, mesquite, coarse grass and shrubs, and on fence posts, and telephone poles, 

 even to the very top, in full glare of the hot sun" (Pilsbry, 1946, p. 15). 



Remarks. Bulimulus alternatus mariae is herein reported for the first time in 

 the fossil record. 



Table 3. Measurements of Bulimulus alternatus mariae in mm. 



Section 



and bed Apert. Apert. No. of 



Specimen nos. Length Diam. height width whorls 



22, PI. 2, figs. 10a, b 2, 10 22.7 22.0 8.9 8.4 5% 



24 2,6 



25 2,9 



26 2,6 



27 2,6 



28, PL 2, fig. 7 2,6 



29 2,10 



Euconulus cher sinus trochulus (Reinhardt) 

 PL 2, figs. 5a-c. 



Description. Specimens are in essential agreement with specimens described 

 by Pilsbry ( 1946, p. 242 ) ; however, present specimens possess 6*4 whorls. 



Measurements. Measurements of Euconulus chersinus trochulus are given in 

 Table 4. 



Distribution. According to Pilsbry (1946, p. 242) Euconulus chersinus 

 trochulus is known on the Gulf Coast from Texas and Louisiana, Arkansas, and 

 Oklahoma. 



Ecology. Euconulus chersinus trochulus is a southern species. 



Remarks. Specific determination of this species was made by Dr. J. P. E. 

 Morrison. This species is recorded from the fossil record for the first time. 



27.0 



13.9 



11.0 



9.5 



5i/ 2 



28.5 



15.7 



11.0 



9.9 



614 



27.6 



15.2 



11.1 



11.0 



6 



26.0 



15.0 



10.6 



9.7 



6 



24.2 



14.0 



11.0 



9.2 



6 



27.0 



14.9 



11.2 



10.0 



63/ t 



