Fig. 
. Cleiothyris pectinifera, J. de C. Sowerby. Umbonal view (natural size) of a tes- 
Digs SOs 
10. 
ke 
12. 
13. 
JA. 
15. 
16. 
17. 
PLATE X. 
tiferous specimen. Tynemouth Cliff. 
so = Large valve of last specimen, showing the pectinated 
expansions. 
nae ae Small valve of the same, showing the emarginate 
foramen (a). 
ae = Lateral view of the same, showing the pectinated ex- 
pansions. | 
— Cast of large valve, natural size. Humbleton Hill. 
rr = Umbonal view of the last specimen. 
ce = Magnified view of the pectinated expansions. 
mae — Enlarged view of the inside of the posterior half, showing 
the hinge-structures of both valves: a, dental plates ; 
6, foramen in the crural base or platform ; e, teeth : 
/, dental sockets. Humbleton Hill. 
ne == Enlarged view of the hinge-structures of the small valve : 
a, crural base or platform ; 6, foramen in do. ; c, button 
or cardinal muscular fulcrum; d, origins of the crura 
of the spirals. 
ae an Enlarged view of one of the spirals, showing it to be fringed 
on the outer edge. Humbleton Hill. 
Martinia Clannyana, Aimy. Cast, twice the natural size; large valve. Ryhope 
Field-House Farm. 
aoe. aa Small valve of the last specimen. 
— = Umbonal view of the same, exhibiting area and fissure. 
Martinia Winchiana, Aimy. Cast (enlarged) of large valve. Whitley. 
— — Cast (enlarged) of small valve. Whitley. 
a ae Umbonal view, showing area and fissure. Whitley. 
= —— Restoration of the large valve. | 
(I was formerly of opinion that in this species the valves were covered 
with radiating hair-like spines; but of late I have been led to 
think that the characters inducing this opinion, are merely due 
to the fibrous structure of the shell. It is therefore extremely 
doubtful that the shell possessed any spines as represented in 
the restoration.) 
