360 0. C. Marsh—Description of Hesperornis regalis, 
three of these sub-genera there are species which have the large 
muscular impressions of the ventral valve obliquely striated or 
grooved. This seems to show that the muscles were not single, 
but composed of several bands. The three genera pass gradu: 
ally into each other, and yet I think some sort of a subdivision 
is required, It seems almost absurd to place such shells as 7, 
grandis and O. Canadensis in the same generic group. 
Proposed new yenus of Pteropoda. 
Genus HYOLITHELLUS, gen. nov. 
Since the sheet containing the description of Hyolithes micans 
was printed off, I have arrived at the conclusion that a new 
genus for its reception should be instituted. I propose to call 
it LHyolithellus. It differs from Hyolithes, in its long slender 
form and in the peculiar structure of its operculum. 
Montreal, 23d March, 1872. 
ART. XLVUI— Preliminary Description of HESPERORNIS BE. | 
GALIS, with Notices of four other new Species of Oretaceous Birds; — 
by O. C. Marsa 
of its affinities. This interesting discovery has already been 
announced in this Journal, and the name, Hesperornis wa 
proposed by the writer for the species thus represented.t, pre 
present paper is preliminary to a full description, with ee 
some new forms to the limited avian fauna heretofore found 1 
the Cretaceous beds of the Atlantic coast. 
Hesperornis regalis, gen. et sp. Nov. an 
_ The remains of this species at present known consist 0 por 
tions of one skeleton, including the nearly entire “tthe 
limbs, from the femur to the terminal phalanges, per ibe 
pelvis, several cervical and caudal vertebra, and numero oe 
( i 5 1872. 
* This Journal, vol. xlix, p. 205, March, 1870. + Volt iii, p. 56, ae ii 
