114 ROYAL SOCIETY OF CANADA 
Arca (below the Lignite), Departure Bay, Nanaimo, Dr. Hector, 1860 ; 
coll. by Mr. Mackay.” A specimen from the same locality, labelled No. 
45, is a cast of the interior of both valves of a shell which may be refer- 
able to this species, but which has unusually tumid or ventricose umbones. 
A second specimen from the same locality (the No. 47 of the list of 
specimens on page 243 of Capt. Palliser’s report), although labelled 
“ Exogyra ? sp.’ seems to the writer to be a distorted left valve of a shell 
which is essentially the same as the specimen labelled No. 45. A third 
specimen is a coarse cast of a left valve of a species of Arca, which is too 
imperfect for identification. 
In the above synonymy the name “ Nemodon Vancouverensis’’ (nobis) 
is omitted, as the writer is not satisfied that the large shells referred to 
on page 163 and figured on plate 19 of the second part of the first volume 
of ‘Mesozoic Fossils,’ are the adult state of A. Vancouverensis, as was 
then supposed. 
TRIGONIA Evansana, Meek. 
Trigonia Evansana, Meek. 1857. Trans. Albany Inst., vol. iv., p. 42. 
Trigonia Emoryi, Etheridge. 1861. In Hector’s paper, Quart. Jour. Geol. Soe. 
Lond., vol. xvii., p. 432, but not 7. Emoryi, Conrad, 1857. 
fé “ Etheridge, 1863. No. 40 of the list of specimens on p. 243 of Capt. 
Palliser’s report. 
Trigonia Evansii, Gabb. 1864. Geol. Surv. Calif., Palæont., vol. i., p. 189, pl. 25, fig. 17. 
Trigonia Evansi, Meek. 1876. Bull. U.S. Geol. and Geogr. Surv. Terr., vol. ii., no. 
4, p. 359, pl. 2, figs. 7, 7a and 7 b. 
Trigonia Evansana, Whiteaves. 1879. Geol. Surv. Canada, Mesoz. Foss., vol. i., 
pte2sip: 161: 
Ten specimens, mostly mere casts of the interior of single valves, 
each labelled “No, 40, Trigonia Emoryi, Conrad ; below the lignite, Depar- 
ture Bay, Nanaimo, Dr. Hector, 1860 ; collected by Mr. Mackay.” 
In 1876 (op. cit., p. 360) Mr. Meek pointed out that his 7. Evansi 
‘Cis almost certainly the same shell that was referred by Mr. Etheridge, 
among Mr. Hector’s collections from Nanaimo, to 7. Emoryi, Conrad 
(pL iii., fig. 2 a, b, ce, United States and Mexico Boundary Survey Report).” 
“Tt is, however,” he says, “certainly very distinct from that species, not 
only in form and in its decidedly less crenate coste, but more particularly 
in having a smooth, longitudinally sulcate, depressed ridge on each side 
of its escutcheon, not crossed by the costæ. Its costæ are likewise less 
numerous and more prominent.” 
CYTHEREA NITIDA, Gabb. (Sp.) 
Cytherea Leonensis, Etheridge. 1861. In Hector’s paper in the Quart. Journ. Geol. 
Soc. Lond., vol. xvii., p. 432, but not C. Leonensis, Conrad, 
1859. 
Cytherea Conensis (err. typ. for Leonensis), Etheridge. 1863. No. 42 of the list of 
specimens on p. 243 of Capt. Palliser’s report. 
