122 ROYAL SOCIETY OF CANADA 
four plications, three of which are simple and one bifurcating, radiate 
also obliquely forward and outward from it. 
In a letter received in August (1894) the writer was informed 
by Mr. T. W. Stanton (of the U.S. Geological Survey) that he had been 
recently studying a number of specimens of Jnocerami with divergent 
radiating plications, from the Niobrara shales of Colorado, that he has no 
hesitation in referring to the J. digitatus of Sowerby, as re-defined and 
figured by Schmidt and Schluter, and that it seems to him quite likely 
that J. undulato-plicatus, Roemer, is only the young of that species. 
Schluter, in his paper on the Cretaceous Jnocerami, is, indeed, inclined to 
keep these two forms separate, but Schmidt (op. cit.) regards both J. 
undulato-plicatus, Roemer, and J. diversus, Stoliczka, as mere synonyms of 
I. digitatus. Mr. Stanton adds, in effect, that although none of Schmidt's . 
figures of J. digitatus exactly duplicate those of I. undulato-plicatus in the 
‘Mesozoic Fossils,” it still seems to him most likely that the Vancouver 
specimens are young individuals of J. digitatus, a conclusion in which 
the present writer entirely concurs. 
NucuLA Ricwarpsonu. (Sp. nov.) 
Nucula pectinata, Whiteaves. 1879. Geol. Surv. Canada, Mesoz. Foss., vol. i., 
pt. 2, p. 161, pl. 18, fig. 8, but not NV. pectinata, Sowerby, 1818. 
Shell similar to WV. pectinata, but less inequilateral and much shorter 
in proportion to its height, the beaks being more nearly central, the 
posterior side longer and more obliquely truncated, the anterior shorter 
and more broadly rounded at its outer termination. 
The slightly distorted left valve from the lower part of the Trent 
River, Vancouver Island, which was referred with doubt to the N. pec- 
tinata of Sowerby by the present writer in 1879, appears to be sufficiently 
distinct from that species to warrant the new specific name now proposed 
for it, in memory of its discoverer. 
NucuzaA Hornpyensis. (Nom. prov.) 
Plate 3, fig. 2. 
Perhaps a variety of WV. solitaria. Gabb. 
Cfr. Nucula solitaria, Gabb. 1869. Geol. Surv. Calif., Palæont., vol. ii., p. 197, pl. 
32, fig, 94. 
Shell of medium size for the genus, compressed convex, subelliptical 
in marginal outline, rather oblique and very inequilateral. Anterior or 
longer side obliquely subtruncated at its extremity above and rather nar- 
rowly rounded below ; posterior or shorter side very regularly but nar- 
rowly rounded at the end; ventral margin broadly rounded, but rather 
more convex posteriorly than anteriorly ; superior border nearly straight 
