WENLOCK GROUP. 
153 






Case and 
Column of 
Drawers. 
Reference to McCoy’s 
Synopsis: and Figures of Genera. 
Names and References; Observations, &c. 



Sea-Butterflies. 
PTEROPODA. 
Theca, Morris. A straight sheath-like shell 
with a flat ventral surface, and a convex 
dorsal one. It has an operculum, See 
p. 66. 

Theca Forbesii, Sharpe (Quart. Geol. Journ. 
Vol. m1. pl. 18, fig. 1). A beautiful little 
fossil. The back convex, the front flat. 
This is opposite to the character of the 
Bala species 7’. reversa. 
Gd7 
Conularia, Sow. The largest and most elegant 
of ancient Pteropods; which order was of 
greater importance in Cambrian and Silu- 
rian times than it has ever been since. 
Some specimens were at least a foot long! 
Conularia Sowerbyi, Defr. (C. cancellata, Sand- 
berger, Siluria, 2nd ed. pl. 25, fig. 10). The 
graceful bend of the crenated ridges across 
the face of each side distinguishes this 
beautiful and common shell. The section 
is rhomboidal. The carboniferous species 
C. quadrisulcata much resembles it. 
FC 
Gd6é 
Conularia clavus, Salter, n.s. New square sp. 
It is rare to find species with square sec- 
tion; usually the opposite angles are always 
equal, but the section is often rhomboidal ; 
and generally two of the sides are smaller 
than the rest. 
Gd6é 

GASTEROPODA. 
The great difference between the univalve 
and bivalve shells lies in the fact, that in 
the inner side of the spiral curve, 1.e. on 
the right side of the animal, the gill is sup- 
pressed. In Patella, however, both gills are 
present, and Gasteropods are higher, for 
they have a head, often eyes—and some 
species, e.g. all the snails, breathe air. 
Spiral Univalves. 

Numbers and Localities. 

b. 726, Dinas Bran, Llan- 
gollen. 
a. 871, a. 872, huge speci- 
men, Dudley, F. C. 
a. 878, Dudley, F.C. 
