46 
ACTINOPTEUTGII, 
Itchyrhiza mini, J. Leidy, ibid. (1856), p. 221.— Cretaceous 
Greensand; Burlington Co., New Jersey. [The type 
species. Tooth.] 
Itchyrhiza (?) radiaUi, W. B. Clark, Bull. U.8. Geol. Surv- 
no. 141 (1896), p. 60, pi. vii. figs. 2 a-c. — Eocene ; Clifton 
Beach, Maryland. [Hypural and caudal vertebrae; Johns 
Hopkins University.] 
Oricardinus tortus, E. D. Cope, Proc. Amer. Phil. Soc. vol. xvh- 
(18<8), p. 177. — Upper Cretaceous; Kansas. [Maxi a 
and vertebrae ; Cope Collection.] 
Genus ESOCELOPS, nov. 
Syn. Eurygnathus, L. Agassiz, Hep. Brit. Assoc. 1844 (1845),- p- 307 
(name only, non Eurygnathus, Wollaston, 1863). 
A genus known only by the head, which is both depressed and 
elongated. Frontal bones extending close to the occipital boidt* 1 ' 
bent into a slight depression in their hinder portion ; parietal hones 
very small. Mandible comparatively short, and gape of mouth not 
extending to the hinder border of the orbit; mandibular teeth 
stout and conical, laterally compressed, well spaced. Operculum 
simple; branchiostegal rays at least 15 in number; gular pl ate 
extending for not less than three-quarters the length of the 
mandible. 
Esocelops cavifrons, sp. nov. 
[Plate III. figs. l i 2.] 
1845. Eurygnathus cavifrons, L. Agassiz, Hep. Brit. Assoc. I 84 *, 
p. 307 (name only). 
Type. Imperfect head ; British Museum. 
The type species, with skull attaining a length of about O' 1 - 
Maximum width of occiput exceeding the length of the postorbital 
region, and somewhat less than one half the length of the cranium- 
length of mandible about equal to the distance from the end of the 
snout to the hinder border of the orbit. Bones of cranial root 
slightly rugose or pitted; cheek-plates very delicate, ornamented 
with rounded radiating ridges. Operculum somewhat deeper than 
broad, and its width equalling about one third the length of the 
cranium , gular plate widest and spatulate behind, its maximum 
width slightly exceeding one third of its length. 
Form, if hoc. Lower Eocene (London Clay) : Sheppey, Kent. 
