140 
Case and 
Column of 
Drawers. 

Gc8 
Gc8 
Gd4 
FC 
FC 
FC 
Gdl 
Gd 


Reference to McCoy's 
Synopsis: and Figures of Genera. 


Spirigerina, p. 197. 
Hemithyris, p. 203. 
Hemithyris lacunosa, p. 202. 
SILURIAN. 

Names and References; Observations, &c. | Numbers and Localities. 


Retzia Salteri, var. Baylei, Davidson (l.c. 
t. 12, figs. 23—25). Only a longer variety 
than the other. 
Retzia Bouchardi, Davidson (I.c. p. 127, t. 12, 
figs. 26—30, is a common species at Dud- 
ley). 
Rhynchonella, Fischer. One recent species, 
the Rhynchonella psittacea, alone remains of 
this abundant fossil genus. It is common 
in all chalk, oolite, carboniferous and Silu- 
rian deposits; and occurred in the Upper 
Cambrian more rarely. Below this it is 
never found. 
Rhynchonella cuneata, Dalm. (Siluria, 2nd 
ed. pl. 22, fig. 8. Dav. Sil. Brach. p. 164, 
t. 21, figs. 7—12). A common Dudley fossil. 
Rhynchonella, n.s. Sharp plaits, like young 
Rhyne. nucula. 
Rhynchonella deflexa, Sow. (Davidson, 1.c. 
t. 22, figs. 24—27, Siluria, 2nd ed. pl. 22, 
fig. 10). The shell is not really reversed; 
the ventral valve is so much flatter and 
more hollowed, and the upper valve so very 
convex, that it quite overhangs the other, 
as in several Orthides. 
Rhynchonella Lewisii, Davidson (l.c. t. 23, 
figs. 25—28, Siluria, 2nd ed. Foss. 57, fig. 2, 
p. 250). One of the commonest species; 
and yet one of the last described. The 
pretty fringe-lke arrangement of the lines 
of growth, crossing the radiating ribs, ren- 
ders this a very elegant shell. 
Rhynchonella borealis, Schloth. (2. lacunosa, 
Dalm.), but not of Linnzeus. (Salter, Mem. 
Geol. Sury. Vol. 1. pt. 1, pl. 28, figs. 9—14.) 
The four plaits in the sinus, and the pointed 
beak, distinguish it. Davidson, Sil. Brach. 
p. 174, t. 21, figs. 14—20, var. figs. 24—27. 

b. 747, Dudley, F. C. 
b. 746, Dudley, F.C. 
a. 910, a. 911, Dudley, F.C. 
a. 769, ordinary variety, 
large; a. 770, with fewer 
ribs, Dudley, F. C. 
a. 759, ventral valve, inte- 
‘rior; a. 760, dorsal valve, 
do.; a. 761, full grown, 
Dudley, F.C. 
a. 767 (interior); a. 768, 
good; b. 751, Dudley, F.C.; 
b. 749, Ledbury; b. 750, 
Wenlock; Whitfield, Tort- 
worth (Earl Ducie). 

