92 
THE GEOLOGIST. 
banded by five or six striae, and the upright portion by four or five. In the body-whorl 
the space posterior to the angle is subcouical, for a secoad angle, which in the smaller 
whorls is the limit of the upright part, and also the line of suture, is here reduced to a 
rib. Posterior to this keel are about eight spiral strife. 
In form this closely resembles P. marginata (D'Orb.) and P. 
Fittoni (Forbes). 
PLErEOTOMARIA JuKESII (u. Sp.). 
Few-whorled, subconical, moderately depressed, half as high as wide, consisting of five 
elevated whorls, which regularly increase in size. The whorls are nearly four times as wide 
as high, and each twice the diameter of that which preceded it. The tilled-in sinus is ele- 
vated like a string and situate ou the upper part of the whorl, which it divides into an 
upper and a lower region. The upper is very convex, deeply impressed at the suture, 
horizontal, and rather narrower than the lower region, which is flat and oblique, being 
inclined at an angle of about 60°. The slit of the sinus is equal in length to the dia- 
meter of the shell. The whole of the upper side is marked with very fine and close 
spiral ribs. 
Under side not seen. 
Most nearly related to P. perspectiva in form of whorl, but well 
distinguished by its few whorls. 
Trochus. 
Shell conical, three-fourths as high as wide ; composed of about four whorls, which 
are flat, one-foui-th as high as wide, and have the sulures deeply impressed. Each whorl 
is ornamented with four spiral striae, of which each supports a row of sharp, elevated tuber- 
cles. The tubercles are separated by spaces about as wide as those which divide the 
rows. The tubercles of the anterior rows are successively placed one between two tubercles 
of the row above, so that other oblique rows are formed parallel to the labial side of the 
shell. The base is flat and spirally striate. 
Teochus. 
Conical, a little higher than wide, not umbilicated ; commonly composed of four or five 
whorls, which are slightly convex. Each whorl is about two and a half times as wide 
as high and encircled by about six spiral striae, which are elevated like cords ; the inter- 
spaces are much wider than the ribs ; they are flat. The highest rib is larger than the 
others, and in most cases less projecting ; it and all the other costse are crossed by very nu- 
merous, oblique, narrow indentations, giving to each rib the look of a twisted rope. The 
side passes under to the base in a large curve. The base is marked by a greater number 
of striae than the side ; they are less elevated, rather closer together, and not bead-like. 
Shell rather thick. The sutm-e is wude and deeply impressed. 
Very nearly related to T. Geinitzii (Rss.). 
(?) FUSTIS. 
Subangularly fusiform ; composed of four or five whorls. Spire ncariy half the length 
of the shell. ^Vhorls angular, rapidly enlarging, twice as wide as high. Ornamented 
with four sharp, narrow, rather elevated ribs, below which, towards the columella, are a 
number of fine stria;, rather distant apart. The whorls are so coiled that two. (? one) of 
the four costae are covered by the body-whorl. The most prominent rib is the most 
posterior, which projects like a cord. The space between it and the suture is flat and in- 
clined at a small angle, and the space below it, for half the body-whori, is parallel to the 
axis. The slope of the ledge of the upper part of the whorl a'ppears to become greater 
as the shell increases in size. Mouth pear-shaped. The shell is finely striated spirally, 
there being some twelve lines between two ribs, and these stria are crossed by still finer 
