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. Pl. IX, figs. 1, 2, 3. 
Shell very small, biconcave, the spiral narrower and more deeply 
sunken on the left than on the right side. Whorls about 23, 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 strie. 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 débris. 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 about 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, pl. 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 débris 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 8. 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 (EK. 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 Mexico. 
