202 
ACriNOPTEKTGII. 
1808. Ischyrocephalus cataphractus, W. von der Marck, he. cit. vol. xv. 
p. 281, pi. xlii. fig. 3, pi. xliii. fig. 8. [Imperfect fiyfi ; Academy 
of Miinster.] 
1873. Ischyrocephalus gracilis, W. von der Marck, loc. cit. vol. xxii. 
p. 58, pi. i. fig. 2. 
1885. Ischyrocephalus cataphractus — Ischyrocephalus gracilis, W. von 
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, attaining 
a length of about 0‘35. Length of head with opercular apparatus 
much exceeding the maximum depth of the trunk and occupying 
one third of the total length to the base of the caudal fin. The 
mandible, operculum, and most of the other external bones orna¬ 
mented with fine tuberculated ridges. Maximum depth of man¬ 
dibular ramus contained about four times in its total length. 
Vertebrae about 50 in number. Pectoral fins with 14 or 15 rays; 
pelvic fins much smaller, with at least 6 rays, arising opposite the 
origin of the dorsal; dorsal fin with 18 rays, of which the three 
foremost are gradually lengthening spines; anal fin arising much 
nearer to the pelvic fins than to* the caudal and comprising 25 rays, 
of which the three foremost are gradually lengthening spines. 
Dorsal scutes four in number, elongate-rhomboidal in shape, and 
ornamented with delicate radiating lines. 
An impression of the adipose dorsal fin has-been observed in this 
species, opposite the hinder part of the anal fin. 
Form. Loc. Upper CretaceousWestphalia. 
P. 3848. Abdominal region of small, fish,, showing impression of 
operculum and remains of the pectoral, pelvic, and dorsal 
fins ; Sendenhorst. Ennishillen Coll. 
Enchodus macropterus (W. von der Marck). 
1863. Ischyrocephalus macropterus, W.. von der Marck, Palaeontogr. 
vol. xi, p. 29, pi. hi. fig. 4. 
1868. Ischyrocephalus intermedins, W. von der Marck, loc. cit. vol. xv. 
p. 282, pi. xliii. fig. 1. [Imperfect anterior portion of fish; 
Academy of Munster.] 
1885. Ischyrocephalus intermedms — Ischyrocephalus macropterus, W. 
von der Marck, loc. cit. vol. xxxi. p. 249. 
Type. Imperfect fish.; Academy of Miinster. 
An imperfectly defined species much resembling E. gracilis, but 
attaining a somewhat larger size and apparently with a smaller 
head in proportion to the length of the trunk. The mandible seems 
