I cragin.] DESCRIPTIONS OF SPECIES. 9] 
rounded, and gradually becoming noticeable as it recedes from it at 
half a turn from the aperture; the same angulation apparently 
continued on the lower part of the spire whorls; base of first spire 
whorl rising abruptly from the upper margin of the body whorl, the 
suture thus being strongly indicated ; surface of shell devoid of trans- 
verse (vertical) ribs or nodes, plain, crossed with finer and coarser 
growth lines. 
Measurements,— Height, about 20 mm.; breadth, 18.5 mm. 
Occurrence.—- One specimen, obtained in foothills at the northwest 
end of Malone Mountain, about 2 miles east-southeast from Finlay 
station. 
Nerita peroblata sp. n. 
PI. XIX, figs. 16, IT. 
Shell obliquely-depressed oval, consisting of 2 whorls; spire 
involved, or rising but feebly above the adjoining whorl border; 
body whorl rapidly increasing its centrifugal expansion with spiral 
distance from its origin, convex on its outer and lower parts, flattish 
on an upper zone which is limited below by an obsolescent spiral 
ridge; aperture semicircular; inner lip without teeth, bearing a 
thick, flat-surfaced callus; outer lip with simple acute border: sur- 
face of shell plain, presenting, besides the obsolescent spiral ridge, 
only growth lines, some of which, more pronounced than the others 
and occurring at irregular intervals, constitute coarse constrictions and 
ridges wdiich are conspicuous also on parts of the cast from which the 
shell has been removed. Of the outer lip in the type only the lower 
border is preserved, but this shows the simple and acute character 
above described. 
Measurements. — Height, 41 mm. (of which the spire occupies barely 
2) ; breadth, 44 mm.; height of aperture, 35 mm.; greatest (obliquely 
centrifugal) diameter of same, 29 mm. 
Occurrence. — Known only by one example, which was associated 
with Nerita nodilirata* etc., H miles east of Malone station. 
Max Schlosser a comments on the Jurassic forms of this genus as 
follows, translated : 
The Jurassic Neritas are distinguished from the typical by the imperfect 
(Nerita chromatica Zitt.) or wholly obsolete toothing of the inner lip (Nerita 
pitteli, neumayri). The outer lip is always simple with cutting border. As 
the only departure from this, one observes a greater or less thickening. On 
the inner lip appears a mostly very strong, often indeed high-arched callus. 
The general habit, however, agrees so well with the recent forms that the 
erection of a new subgenus appears inadvisable. 
a Die Fauna der Kelhoimer Dieeras-Kalkes : I'alaeontographica, vol. 28, \>. 93. 
