FOSSILS OF THE DEVONIAN. 109 
1, p. 13, fig. 3. 1874), from the Gaspé limestone, but differs in surface char- 
acters. 
Formation and locality —In the lower horizon of the Devonian limestone 
of Lone Mountain, 18 miles northwest of Eureka, Nevada. 
Lingula Whitei, n. sp. 
Plate xiii, fig. 3. 
Shell above the average size, subelliptical in outline, the length and 
breadth as 5 to 3; the cardinal slopes of the dorsal valve converge at an 
angle of 20°; front broadly rounded and sides subparallel, curving slightly 
outward. ‘The dorsal valve is quite convex and a little flattened along the 
center towards the front. 
Surface marked by fine concentric and radiating strie, and when 
the outer shell is partially decorticated strong radiating lines, crossed by 
raised concentric strix, give a somewhat reticulated appearance to the sur- 
face. The length of the specimen described is 29"™ and the breadth 17™. 
The general outline of the species is similar to that of Lingula squamt- 
formis Phillips (Mon. Brit. Foss. Brach. Davidson, vol. ii, p. 205, pl. xlix, 
figs. 1-10), of the Carboniferous rocks, but the valves are more convex 
and the scars on the interior of the dorsal valve differently arranged. I 
know of no closely related Devonian species. 
A cast of the interior of the dorsal valve was obtained from a fragment 
of limestone in which the shell adhered to the matrix by its exterior sur- 
face and left the imprint of the vascular markings and muscular scars 
beautifully and distinctly defined on the cast. It is of great interest, as it 
affords the opportunity for the comparison of the structure with that of living 
forms of the genus, and shows that the strong generic resemblance of the 
outer surface of the shell to that of recent species is also present in the 
more important muscular scars on the interior surface. 
At the posterior end, just within the apex of the valve, the cast of the 
elongate divaricator muscular scar (d, plate xiii, fig. 3) is well impressed; 
it is transverse and arches forward a little at the sides, back of the initial 
points of the path of the advance of the posterior adductor and adjustor 
