PACHYCORMID^E. 
391 
in length and are not branched distally ; pelvic fins small; dorsal fin 
partly or completely in advance of the anal, which is much extended; 
caudal fin very deeply forked. Scales small and deeply imbricating, 
those of the ventral aspect much broader than deep; lateral line 
inconspicuous. 
So far as known, the osteology of this genus is almost identical 
with that of Pachycormus, as already described; but there is a 
distinct premaxilla and the dentition is much more powerful. The 
same characteristic arrangement of the suborbital and circumorbital 
bones is observable; the sclerotic is also well-ossified; and the 
posteriorly-placed supramaxilla is identical in the two genera. The 
maxilla does not articulate directly with the cranium or pterygo¬ 
palatine arcade, but is suturally united with the premaxilla; and 
the latter element is apposed to an extended groove in the lateral 
ethmoidal region along its narrow antero-superior border. The 
vomers are clearly shown to be fused with the mesethmoid; and 
their pair of large teeth is directly opposed to a similar pair in the 
splenials. The latter elements are much thickened where they 
meet in the mandibular symphysis ; but they rapidly taper back¬ 
wards, again expanding in the hinder half of the ramus into a thin 
laminar plate apparently covering the whole of the inner face of 
the jaw and armed with minute, almost granular teeth. The teeth 
of the dentary are borne on a thickened ledge on the inner face of 
the bone. Between the mandibular rami there is a large, azygous 
gular plate, followed by a numerous series of short branchiostegal 
rays. The only important differences in the trunk seem to be, the 
presence of small pelvic fins and the elongation of the anal fin. 
Hypsocormus insignis, Wagner. 
[Plate XIY. fig. 1.] 
1860. Hypsocormus insionis, A. Warner, Gelehrte Anzeig. k. bav. 
Akad. Wiss. vol. 1. p. 221. 
1863. Hypsocormus insignis, A. Wagner, Abh. k. bay. Akad. Wiss., 
math.-phys. Cl. vol. ix. p. 677. 
1881. Hypsocormus insignis, B. Vetter, Mittheil. k. mineral.-geol. Mus. 
Dresden, pt. iv. p. 95. 
1887. Hypsocormus insignis, K. A. von Zittel, Handb. Palaeont. vol. iii. 
p. 226, woodc. fig. 239. 
Type. Imperfect fish; Palaeontological Museum, Munich. 
The type species, attaining a length of about 0*7. Length of 
head with opercular apparatus equalling about one-quarter of the 
total length to the base of the caudal fin, and less than the maxi¬ 
mum depth of the trunk. Snout short and obtuse, and external 
