


cea Reference to McCoy's 
Drawers. Synopsis: and Figures of Genera. 
FC 
I 
S 
SS 
() 
Gc7 
FC 
FC 



Pl. 1 4, figs. 4, 5, p. 255. 
See Athyris. 

WENLOCK GROUP. 
135 

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

BRACHIOPODA (Palliobranchiata). 
Are easily divisible into (1) horny and hinge- 
less shells (Lingula, Discina, Obolus), 
and (2) hinged calcareous shells, Orthis, 
Spirifer, &e. The passage from the young 
Lamellibranch to the Brachiopod is easily 
seen by laying open a young <Anodon 
(Rathke’s Memoir). The heart is double, 
the intestine duplicate; the form of the 
opened valves, like that of Orthis biloba, 
and the median plate in so many Brachio- 
pods, is the sure indication of the real 
nature of these otherwise anomalous Bi- 
valves. 
Crania, Retzius. A well-known recent genus, 
which, with slight modifications, and very 
slight ones, has persisted from the Lowest 
Bala group to the present day. It inhabits 
deep water usually. 
Crania implicata, Sow. sp. (Patella? in the Silu- 
rian System. Orbiculoidea of D’Orbigny. 
Crania, Salter, Siluria, 2nd ed. pl. 20, fig. 4, 
Davidson, Sil. Brach. p. 80, pl. 8, figs. 13—17). 
The shell is a minute oval, imbricate outside, 
and with strong muscular scars. 
Crania Grayii, Davidson. 
figs. 22—24.) 
(Sil. Brach. pl. 8, 
Trematis (Discina) Siluriana, Davidson. (Sil. 
Brach. pl. 8, figs. 19—20.) 
Spondylobolus, McCoy. A genus unfortunately 
founded in mistake; a species of Meristella 
(probably MZ. obovata) being so pressed in 
shale, as to thrust the teeth through the 
opposite valve, and give rise to deceptive 
appearances. The formation also (this was 
not the Professor’s error) is erroneous: The 
shell comes not from the black Lower Bala 
rocks of Builth, but from the equally black 
Wenlock shale. See No. 382. 


a. 395, Dudley, F.C. 
a. 713, Dudley, F.C., 
three specimens. 
a. 809, a. 810, Dudley, 
F.C. 
