EXCHODOXTIDJE. 
213 
Type. Imperfect fish, wanting tail; Royal Bohemian Ilusenm, 
Prague. 
The type species, attaining a length of about I'O. Length of 
head with opercular apparatus contained approximately three times 
in the length from the pectoral arch to the base of the caudal fin. 
Operculum comparatively smooth, its breadth about two thirds as 
great as its maximum depth. Yertebrse about 45 in number. 
Form. Log. Turonian : Bohemia. 
P. 5732. Plaster cast of type specimen; .Jung Koldiu, Bohemia. 
Presented hy Prof. Anton FritscJi, 1888. 
P. 9002-04. Three imperfect specimens in irregular fragments ; 
Yinary, Bohemia. Purchased^ 1899. 
■ Halec eapterygius (Dixon). 
1837. Osmeroid.es lewesiensis, L. Agassiz, Poiss. Foss. vol. v. pi. lx b. 
figs. 3, 4 (errore). 
(?) 1844. Osmeroides gi'anulatus, L. Agassiz, ibid. vol. v. pt. i. p. 14 
(name only). 
1850. Pomognathus eupterygius, F. Dixon, Geol. Sussex, p. 367, 
pi. XXXV. figs. 6, 7. 
1888. Pomognathus eupterygius, A. S. lYoodward, Proc. Geol. Assoc, 
vol. X. p. 318. 
Type. Imperfect fish ; Brighton Museum. 
The type species of the so-called Pomognathus., attaining a length 
of about 0‘4. Length of head with opercular apparatus much 
exceeding the maximum depth of the trunk, which is probably 
contained about four times in the length from the pectoral arch to 
the base of the caudal fin. Length of mandible somewhat exceeding 
the depth of the head at the occiput; operculum considerably 
deeper than broad; the infero-posterior spine of the preoperculum 
short, stout, and ornamented with tubercles. The external 
tubercular ornament very fine, arranged in more or less radiating 
lines on the sides of the cranial roof, the supramaxilla, mandible, 
opercular apparatus, clavicle and supraclavicle. The stouter rays 
of the paired and dorsal fins also ornamented with longitudinal 
series of verv fine tubercles. Yertebrse about 45 in number. 
The squamation of this species is unknown, probably on account 
of the soft nature of the chalky matrix in which the specimens are 
preserved. 
Form. 4)' Log. Turonian and Senonian : Rent and Sussex. 
43388. Remains of small fish, in counterpart; Lower Chalk, Bur- 
ham, Kent. The general proportions are as stated in the 
