396 
ACTINOPTERYGII. 
Genus HOPLOPTERYX, Agassiz. 
[Poiss. Poss. vol. iv. 1838, p. 4.] 
Trunk much deepened and laterally compressed. Prontal region 
of skull deeply ridged for mucus-cavities; cleft of mouth little 
oblique, and jaws with very minute teeth ; orbit small or of mode¬ 
rate size ; preoperculum without spine, only serrated. Yertebrm 
about 10 ill the abdominal, 14 in the caudal region. Pelvic fins 
arising below or somewhat behind the origin of the pectorals, 
with one stout spine and 7 or 8 divided rays. Dorsal fin much 
extended, its anterior half consisting of 5 to 9 stout spines, not 
closely pressed together; anal fin comparatively short, with 3 to 5 
stout spines, not closely pressed together; caudal fin more or less 
deeply cleft. Scales ctenoid, rather large, rarely ornamented with 
granulations, and none much enlarged or thickened ; lateral line 
forming a conspicuous discontinuous ridge. 
Hoplopteryx antiquus, Agassiz. 
1838-39. Hoplopteryx antiquus, L. Agassiz, Poiss. Foss. vol. iv. pp. 4, 
131, pi. xvii. figs. 6-8. 
1858. Hoplopteryx antiquus, W. von der Marck, Zeitschr. deutsch, 
geol. Ges. vol, x. p. 252. 
Hoplopteryx antiquus, var. minor, W. von der Marck, Palgeontoo-r. 
vol. xi. p. 13, pi, i. fig. 4. 
1863. Hoplopteiyx antiquus, var. major, 'W, von der IMarck, loc. cit, 
vol. xi. p. 14, pi. ii. fig. 1. 
1885. Hoplopteryx antiquus, W. von der Marck, loc. cit vol xxxi 
p. 243. 
Type. 1^'early complete fish; Palaeontological Museum, Munich. 
The type species, attaining a length of about 0-3, but usually 
smaller. Length of head with opercular apparatus nearly equal to 
the maximum depth of the trunk, and contained about one and a 
half times in the length from the pectoral arch to the base of the 
caudal fin. Origin of pelvic fins opposite to that of the dorsal, 
which occupies one half the length of the back (measured from 
occiput to caudal fin), comprising 6 ribbed spines and 11 divided 
rays ; anal fin with 4 similar spines, gradually increasing in length, 
and 9 or 10 divided rays, terminating behind slightly beyond the 
dorsal. 
Form. ^ Loc. Upper Cretaceous : Westphalia. 
There is no typical example of this species in the Collection, but, 
as observed by W. von der Marck {he. cit. 1885), the small’form 
