90 M ALONE JURASSIC FORMATION OF TEXAS. [bull. 200. 
specimens were collected, four of them by Doctor Stanton, after 
whom the species is named. 
ISTERITID^E. 
Genus NERITA Linmcus. 
NERITA NODI I.IK ATA S}). 11. 
PL XX. figs. 1-4. 
Shell thick, composed of *2\ to 3 whorls, its very obtuse-apexed inte- 
rior cast loosely coiled and making only about a revolution and a 
half; body whorl obtusely angulated above the middle, somewhat 
concave above the angulation and again convex above the concave 
zone; spire very small, rising but little above the body whorl; 
aperture semilunar; peristome considerably thickened below; colu- 
mellar area broadly flattened and overspread with a callus; whorls 
transversely trenchant-striate, or marked with close and abruptly 
elevated transverse lines, and bearing tubercular or noded ribs; 
exposed parts of the spire whorls and the corresponding (upper) pari 
of the body whorl bearing rather remote, compressed, transverse ribs, 
each of which bears 2 remote nodes (the lower node being at the locu., 
of angulation in the body whorl and just above the inferior suture in 
spire whorls), these ribs continued as simple ridges across the lower 
part of the whorls in very young shells, but on the body whorl of older 
ones giving place to 4 or 5 revolving interrupted ribs or rows of lowJ 
elongate granules or tubercles. 
Measurements. — Height, 27 mm.; breadth, 30 mm.; these dimen 
sions representing considerably less than the maximum size. Tli 
two largest specimens at hand, though too imperfect for exact meas- 
urement, indicate dimensions between one-third and one-half greaterJ 
Occurrence. — Especially abundant, with Natica icilliamsi and other 
( irasteropoda, in lower strata of the exposed part of the Theta, between 
the Trio and the Truncate mound, being represented in niv collection 
by 54 specimens. 
The species belongs to the subgenus Lissochilus. 
Nerita finlayensis sp. n. 
PL XIX. fig. 15. 
General form somewhat like that of N. nodilirata, both body whorl 
and spire, however, a little more elevated; whorls few; body whorl 
with an even, obtuse, revolving angulation near the middle, the sam< 
being obsolete near the aperture, where the shell is almost evenl 
