FOSSILS OF THE DEVONIAN. 133 
present various stages of development, from a simple trace on the front 
margin to where they pass up over the center. 
The form from the Mackenzie River Basin, illustrated by Mr. Meek and 
not specifically identified, is very closely related to the semicostate variety, 
if not identical with it, and it occurs in association with Rhynchonella castanea, 
a form found with P. (P.) lachrymosus vay. stigmatus, at Rescue Hill. 
Formation and localities—Upper horizon of the Devonian limestone, 
Rescue Hill, and The Gate, northwest of Eureka, Nevada. 
Productus (Productella) speciosus Hall. 
Plate xiii, fig. 8. 
Productus speciosus Hall, 1857. Tenth Ann. Rep. N. Y. State Cab. Nat. Hist., p. 176. 
Productella speciosa Hall, 1867. Pal. N. Y., vol. iv, p. 175, pl. xxv, figs. 1-11. 
This beautifully marked species occurs in the same beds with the vari- 
eties of P. (P.) lachrymosa, but it is so distinctly.characterized by a narrow, 
somewhat attenuate umbo and the closely arranged smaller and more numer- 
ous spiniferous tubercles that there is little danger of confounding the two 
species. Of the identity of the New York Chemung Group specimens and 
those from the Eureka District there is hardly an opportunity to suggest a 
point in opposition, as they closely coincide in all their specific characters. 
Formation and localities —Upper horizon of the Devonian limestone, 
Rescue Hill, and at The Gate, northwest of Eureka, Nevada. = 
Productus hirsutiforme, n. sp. 
Plate ii, figs. 10, 10a. 
Shell thin, transversely semicircular; width less than the length, unless 
distorted by compression; hinge line equaling or a little less than the width 
of the shell. 
Ventral valve moderately convex and without median sinus, rather 
abruptly depressed toward the cardino-lateral margins, which are flattened 
and broadly auriculate; beak small, incurved. Dorsal valve concave and 
following the curvature of the ventral one. 
