Fi 
15. 
16. 
hve 
PLATE XII. 
: Strophalosia Goldfussi, Minster. Cast, large valve, natural size. Ryhope Field- 
House Farm. 
Cast, small valve, natural size. Ryhope Field-House 
Farm. 
Cast, large valve, natural size: a, Cardinal and valvular 
muscular scars confluent. Humbleton Hill. 
Cast, large valve, natural size. -Ryhope Field-House Farm. 
Representation (copied from a gutta-percha cast of fig. 9) 
of imner surface of small valve, showing boss or cardinal 
muscular fulcrum (a); dental sockets (6); median 
plate (¢); impression of vein connecting the reniform 
lobes with the medio-cardinal region (d); reniform 
lobes (e) ; posterior division of the valvular muscles (/) ; 
anterior division of the same (4). 
Cast (natural size) of small valve, and area of large valve 
Ryhope Field-House Farm. 
Testiferous specimen. Same view (natural size) as last: 
a, area; 6, deltidium. Ryhope Field-House Farm. 
Cast, same view (natural size) as last. Humbleton Hill. 
Cast, natural size, showing depressions of the teeth of the 
large valve (a). Humbleton Hull. 
Cast of a young specimen. Humbleton Hill. 
Cast (nearly twice the natural size) of a young specimen. 
Ryhope Field-House Farm. 
Gutta-percha cast of the area (a), and deltidium (4) of the 
large valve. Original from Ryhope Field-House Farm. 
. Strophalosia excavata, Geiitz. Gutta-percha cast of the large valve, natural 
size, Showing the spines. Original from Dalton-le-Dale. 
Cast, small valve. Humbleton Hill. 
Gutta-percha cast of small valve (crowded with spines), 
and areas. Dalton-le-Dale. 
Cast, small valve. Humbleton Hill. 
Gutta-percha cast of area of both valves: a, large valve; 
c, small valve. Original from Dalton-le-Dale. 
18. Strophalosia Morrisiana, Avg. Small valve (natural size) of a testiferous specimen. 
Tunstall Hill. 
(The spines are preserved on the large valve only). 
