ANTHRACOMYA VALENCIENSIS. 113 
the V-shaped arrangement of the wrinkles is at right angles to that which obtains 
in the left valve, and that the condition is purely accidental. Mr. Salter says of 
this shell (loc. supra cit.), “ The general appearance is that of an ordinary convex 
Modiola ; but the epidermis, deeply wrinkled v-fashion over the posterior slope, 
shows its true affinity.’ He goes on to say, relying on this quasi-affinity to 
Myadz which he allowed to overbalance the evidence afforded by shape, “ We 
cannot get at the interior, but there is not much doubt that there is a pallial sinus, 
and there were probably long siphonal tubes covered by a thick epidermis, the 
animal burrowing in the mud as most of the Myade do’’—a condition which 
subsequent investigation has shown to be absent. It was only under the head of 
A. senex that any observations are made with regard to the generic affinity of 
Anthracomya, and it is probable that the wrinkled periostracum of A. senex was 
the chief factor in referring this genus to the Myade. I have on this account 
gone into the details given by Mr. Salter, and have quoted fully from his remarks. 
A. senex is a rare shell, and I have only met with one other specimen from South 
Wales, also in the collection of the Geological Survey, but have obtained a few 
from the Hard-mine and Cockshead Ironstone of North Staffordshire, but in these 
beds it appears to be very rare. This species is easily distinguished from all 
others by its oblique wedge-shaped gibbose form, and by the raised hinge-line 
posteriorly and strongly marked diagonal keel. 
11. Anraracomya Vatencrensis, R. Etheridge, jun., nov. sp. Plate XVI, 
figs. 44—48. 
Specific Characters.—Shell small, pisiform, tumid. The anterior end is small, 
regularly swollen, and has a convex border. The posterior end is expanded and 
compressed with a bluntly convex border. The inferior border is almost straight, 
passing with a gradual curve in front and behind into the anterior and posterior 
borders. The hinge-line is straight, elevated posteriorly, somewhat shorter than 
the greatest antero-posterior measurement of the shell. The umbones are small 
and inconspicuous, slightly raised above the hinge-line, and non-contiguous. The 
shell is evenly swollen in an oblique direction, the swelling being soon lost on the 
surface of the shell. 
Interior.—Not known. 
Exterior.—The surface is covered with fine lines and strive of growth which 
run parallel to the anterior inferior and posterior borders. The periostracum is 
wrinkled. 
15 
