202 
ACTIN OPTERYGII . 
1808. Ischyrocephalus cataphractus, W. von der Marck, loc. cit. '°j' * 
p. 281, pi. xlii. fig. 3, pi. xliii. fig. 8. [Imperfect fish ; Aca e 
of Munster.] • • 
1873. Ischyrocephalus gracilis, W. von der Marck, loc. cit. vol. x - 
p. 58, pi. i. fig. 2. n 
1886. Ischyrocephalus cataphractus = Ischyrocephalus gracuis, 
der Marck, loc. cit. vol. xxxi. p. 249, pi. xxii. figs. 3, 4. 
Type. Imperfect fish ; Academy of Munster. . . 
The type species of the so-called genus Ischyrocephalus, attain 
a length of about 035. Length of head with opercular app ara _ 
much exceeding the maximum depth of the trunk and occup} ^ 
one third of the total length to the base of the caudal fin. 
mandible, operculum, and most of the other external bones 
mented with fine tuberculated ridges. Maximum depth ot ® ^ 
dibular ramus contained about four times iu its total ^ _ 
Vertebrae about 50 in number. Pectoral fins with 14 or ^ 
pelvic fins much smaller, with at. least 6 rays, arising opp 091 ^ 
origin of the dorsal; dorsal fin with 18 rays, of which t e ^ 
foremost are gradually lengthening spines; anal fin ansin J. 
nearer to the pelvic fins than to the caudal and comprising ^ 
of which the three foremost are gradually lengthening S F 
Dorsal scutes four in number, olongate-rhomboidal in s 8 P ’ 
ornamented with delicate radiating lines. - n 
An impression of the adipose dorsal fin has- been observe 
species, opposite the hinder part of the anal fin. 
Form. <$r Loc. Upper Cretaceous:. Westphalia. ^ 
P. 3848. Abdominal region- of Bmall fish, showing iropre- ^ rsa ] 
operculum and remains of the pectoral, pelvic, an 
fins ; Sendeuhorst. EnmsJallen 
Encliodus macropterus (W. von der Marck )• 
1863. Ischyrocephalus macropferus, W. von der Marck,. 
vol. xi. p. 29, pi. iii. fig. 4. j - dt. vol- 
1868. Ischyrocephalus intermedius, W. von der Marc , ° ' 0 j- fish; 
p. 282, pi. xliii. fig. 1. [Imperfect anterior porti 
Academy of Miinster.] rro ptertts, 'V. 
1885. Ischyrocephalus intermedius = Ischyrocephalus ma 
von der Marck, loc. cit. vol xxxi. p. 249. 
Type. Imperfect fish; Academy of Miinster. raC ilis, b ut 
An imperfectly defined species much resembling •17 ^ gina ller 
attaining a somewhat larger size and apparently wi ^ se em s 
head in proportion to the length of the trunk. The man i 
