GASTEROPODA. ' 
133 
TROCHU S, Linnaeus. 
Pal^otkochus, n. subgen. 
Shell conical, trochiform. Spire elevated. Volutions moderately convex. 
Aperture transverse : columella ? 
Pal/eotrociius Kearneyi. 
PLATE XXX, FIG. H. 
Pleurotomaria Kearneyi, Hall. Fourteenth Rep. N. Y. State Cab. Nat. Hist., p. 105. 1861. 
“ “ “ Fifteenth Rep. N. Y. State Cab. Nat. Hist., p. 163, f. 14. 1862. 
Shell large, trochiform. Spire obtusely conical, comparatively short, con¬ 
sisting of four or more volutions, which rapidly increase in size from the 
apex, the last one much expanded. Suture apparently canaliculate from 
a carinate expansion of the preceding volution. The last volution is flat¬ 
tened or slightly concave on the upper third, and prominent above the 
middle along a line of obscure or undeveloped nodes; flattened on the 
lower half, which is separated from the base by a strong, simple, angular 
carina; basal side of the volution prominent in the middle, depressed 
towards the umbilical region. Aperture transverse, somewhat semi¬ 
elliptical, nearly once and a half as wide as high. 
Surface marked by strong unequal strife of growth, which bend backward 
from the suture to the more prominent part of the volution, in crossing 
which they curve a little forward but do not become vertical, and again 
bend more abruptly backward in approaching the carina, over which they 
-pass without sensible change in direction, curving forward on the middle 
of the lower side, and thence backward to the umbilicus. 
This shell attains the dimensions of more than three inches in height; the 
one figured is a little more than three inches in diameter on the base: some 
individuals attain a greater size. So far as known, the surface is marked only 
