1906.] NATURAL SCIENCES OF PHILADELPHIA. 167 
the whorls are rounded, the panetal lamine are as in Planorbula ex- 
cept that the larger one stands more obliquely, the basal lamina i 
transverse, but all the rest on the outer wall are entering plice, the larger 
lower one curving downward a little at its inner end, not upward as in 
armigera and wheatleyi. As in all American forms of the genus only 
one set of laminge seems to be present in any individual, though the 
earliest set is formed at a very early age. In the European and 
Asiatic species several sets are usually present. 
PLEUROCERATIDZ. 
Goniobasis comalensis Pilsbry. Figs. 24-28, 
Melania rufa Lea?, Rémer, Texas, p. 457 (‘‘In den Quellen des Comal- 
Spring bei New Braunfels sehr hiufig’’). 
Melania pleuristriata Say, A.G. Weatherby [Wetherby] American Naturalist, 
April, 1878, p. 254, with var. marmocki (springs ef southwestern Texas). 
Goniobasis comalensis Pils., Nautilus, IV, p. 49, Sept., 1890 (Comal creek, 
New Braunfels). 
G. pleuristriata Say and G. comalensis Pils., Singicy, Contrib. Nat. Hist. 
Texas, Geol. Surv. Tex. Ann. Rep., 1892, pp. 311, 312. 
Shell conic-turrite, thin but strong, covered with an olive-brown 
cuticle. Whorls of the spire with a distinct keel which projects a 
short distance above the suture, and is usually wanting on the last two 
Fig. 25. Fig. 27. 
whorls; the whole surface showing fine sigmoid growth-strie, and in the 
best specimens very faint, minute, spiral striae. Aperture ovate, the outer 
lip thin, sigmoid, retracted below the upper insertion; basal lip rounded 
or subangular. Columella arcuate, somewhat thickened. Whorls 
about 7 in the most perfect shells, but usually fewer, the upper ones 
being eroded. 
Length 18, diam. 7.3, aperture 7.3 mm. 
Comal creek at New Braunfels, Comal county, Texas. Also in the 
