220 PROCEEDINGS OF THE ACADEMY OF [Mch., 



Subgenus METASTOMA Strebel. 

 Holospira roemeri:(Pfr.). PI. XXVI, figs. 10-18. 



This peculiar snail Inhabits the hilly border of the 1,000 foot elevation 

 which roughly defines the southeastern limit of the Lower Cretaceous 

 area in Texas, It has not been observed northeast of New Braunfels. 

 Thence it has been traced westward in Medina county, and near the 

 Rio Grande, at Devil's river and the Pecos. We know nothino; of its 

 distribution northward upon the ''Edwards Plateau," since only its 

 lower scarps have been explored. Westward we have it from El Paso, 

 where Ferriss got specimens on Franklin Mountain in 1902; and in 

 New Mexico Rehn and Viereck found it in Alamo Canyon, near Alamo- 

 gorda, Otero county, in the eastern range of the Cordillera. 



The specimens from El Paso are large, like those of the Pecos. An 

 average one measures, length 15.5, diam. 4.5 mm.; whorls 14. Those 

 from Alamo Canyon are smaller, 12 to 13 mm. long, 4 wide. They 

 vary but little in size. 



In the canyon of the Pecos river, in Valverde county, Texas, above 

 and below the High Bridge (figs. 16, 17, 18), the specimens are larger 

 than at any other locality, and have more whorls for their length. The 

 base is narrowly and deeply excavated, and the last whorl is very 

 strongly sigmoid and projects in a longer neck than in the shells of 

 central Texas. Most of the shells measure 15 to 16 mm. long, 4 wide, 

 few being larger or smaller. 



Length 17, diam. 4.7 mm.; whorls 15^. 

 16, 

 15.5, 

 15. 

 14.9, 



In the drift-debris of Devil's river, Valverde county, Texas, about 

 four miles from its mouth, a large majority of the shells are 14 to 15 

 mm. long, with 14^ to 15J whorls. The base and neck are like the 

 larger shells of the Pecos. 



Length 15.2, diam. 4 mm.; whorls 16. 



" 151. 



15^ 



'3- 



15^ 



15. 



14^. 



14i. 



13f. 



