1906.] NATURAL SCIENCES OF PHILADELPHIA. 165 



in Hays and Comal counties. It is about the size of P. parvus, but 

 the aperture is less oblique and the sculpture differs. It was found 

 with parvus in Comal county and in the Pecos canyon. 

 Planorbis filocinctus n. sp. PI. IX, figs, l, 2, 3. 



Shell very small, biconcave, the spiral narrower and more deeply 

 sunken on the left than on the right side. Whorls about 2f , the last 

 broadly rounded peripherally, rounded also on both sides, but less 

 convex on the right than on the left side. Sculpture of inconspicuous 

 growth-lines and numerous thread-like spiral striae. Color of bleached 

 specimens white or faintly yellowish. Aperture oblique, heart-shaped, 

 about as long as wide, excised moderately by the preceding whorl. 



Greatest diam. of the disk 2.4, alt. (thickness) nearly 1 mm. 



San Pedro river, Benson, Arizona, in drift debris. Types collected 

 by J. H. Ferriss, 1904. 



This little species may be at once recognized by its spiral striation, 

 which is far stronger than in any other North American species. It is 

 flattened less than P. parvus. Only five specimens were taken, but 

 it is so unlike other known Mexican or United States Planorbes that 

 there seems no doubt of its specific distinctness. 



Planorbis parvus Say. 



Guadalupe river al^out four miles above New Braunfels, Comal 

 county; Devil's river, Val Verde county, Texas. San Pedro river, 

 Benson, Arizona. 



Planorbis cultratus Orb. 



Pilsbry, Nautilus, III, p. 63, pi. 1, figs. 1, 2, 3. 



This species is thin and delicate, very acutely carinate at the periphery 

 which is close to the left side. In 1889 one of us reported it from Hidalgo, 

 Texas, where it was taken by Mr. Singley. In 1903 we took a single 

 young shell in the drift debris of Devil's river, Val Verde county. The 

 young have a much less acute keel, in fact are angular rather than 

 carinate, and they are less compressed in proportion. P. cultratus is 

 found also in Florida (collected at Miami by S. N. Rhoads), Central 

 America and the West Indies. Few of the specimens thus far known 

 from Texas are fully mature or in good condition. 

 Planorbis liebmanni Dkr. 



Canal at New Orleans, Louisiana (H. Hemphill !). In Texas at Waco 

 (Hemphill), Austin (E. Hall), San Marcos, New Braunfels, Hondo 

 river, Del Rio, Devil's river and Pecos river (Ferriss and Pilsbry); also 

 in the southeastern part of the state in Victoria county (J. D. Mitchell) 

 and near Brownsville, Cameron county (Clapp). Also in ^lexico. 



