16 
correlations. Wachsmuth and Springer 1 in 1897 described a 
species from equivalent beds in Iowa; and Weller in 1898 2 
described three species and two varieties from shales of the 
Hamilton group at Milwaukee, Wisconsin, which have a facies 
very similar to that of the Missouri species. The whole of the 
Hay River section from which the crinoids described in this paper 
were obtained is referred by Kiftdle 3 to the upper Devonian. 
He finds the Portage fauna in beds below those which furnished 
the crinoids. 
The most abundant crinoid species of the Missouri locality 
is the form described by Rowley as Melocrinus tersus. It is of 
medium size, having a rather elongate calyx, with tumid, but 
according to description not acuminate, plates. A number of 
specimens since obtained from the type locality show a consider- 
able range of variation within the species — all specimens tending 
to have more or less acutely pointed plates, usually confined to 
the radial series ; these are sharper and accompanied by delicate 
radiating ridges in younger specimens, which are represented in 
these respects by Rowley’s M. Lylii . 
The Canadian form numbered 5643 is closely related to the 
prevalent Missouri species, from which it is separable by char- 
acters of minor value — the result of variations due to migra- 
tional changes in a vigorous and wide-ranging type. It may 
take the name — 
Melocrinus borealis n. sp. 
Plate I, figures 1, 2 
A medium-sized species, of the type of M. tersus Rowley, 
but having the calyx proportionally shorter and more rotund; 
plates of the dorsal cup more strongly tumid, often surmounted 
by one to three fine papillae; tegmen plates more numerous, 
flatter, and also bearing fine tubercles. A few brachials pre- 
served in one ray show the arms to be small and delicate. Size 
of largest calyx: height and width each 20 mm. 
*N. A. Crinoidea Camerata, p. 300. 
2 Annals New York Acad. Sc., vol. 11, 1898, pp. 117-124. Wisconsin 
Geol. Surv. Bull. 21, 1911, pp. 38-42. 
3 Geol. Surv., Can., Bull. No. 29, 1919, p. 4. 
