EUGjSTATHIDJE. 
287 
more than one series over the whole of the splenial; preoperculum 
smooth ancl narrow ; suboperculum of moderate size, about half as 
large as the nearly rectangular operculum, and with a short 
ascending process at its antero-superior angle. Ossifications in the 
sheath of the notochord observed only in the largest species; 
ossified ribs slender. Fulcra biserial, well-developed on all the fins 
except the pectorals, on which they are feeble. Pectoral much 
exceeding the pelvic fins in size, but the latter well-developed ; 
dorsal and anal fins triangular in shape, the former arising opposite 
or immediately behind the pelvic fins ; caudal fin forked. Scales 
thick, with a narrow overlapped border, an inner rib, and a feeble 
peg-and-socket articulation; superficial ganoine smooth on the 
anterior half of each scale, passing on part of the body into trans¬ 
verse rugae and crenulations posteriorly; principal flank-scales 
rarely, and then only in part, deeper than broad, several series of 
ventral scales much broader than deep ; postclavicular scales large; 
no enlarged scales on the dorsal ridge or in the region of the anus. 
Lateral line inconspicuous. 
A description of the skeleton of Eugnathus will equally apply to 
Heterolejpidotus (see p. 304), which differs only in minor particulars. 
The chondrocranium is well ossified, and the basicranial axis is 
straight. The basioccipital exhibits on its posterior face a deep 
conical fossa for the notochord; and the inferior aspect of the bone 
is marked by a slight longitudinal groove, though there is apparently 
no basicranial canal. A robust ossification is conspicuous both in 
the postfrontal and in the prefrontal region. Nearly the whole of 
the base of the skull is sheathed by a large parasphenoid, which 
appears to terminate in advance of the occiput and exhibits a pair 
of long hasipterygoid processes. In front of the latter the para¬ 
sphenoid hears a long, lenticular patch of minute granular teeth. 
The vomers are unsatisfactorily known, but a cluster of larger short 
and conical teeth appears to belong to them: they are certainly 
paired in Heterolepidotus. The membrane bones of the cranial roof 
form a continuous shield, which is nearly flat. The parietals 
are small and short, meeting in a remarkably wavy suture which 
makes them an unsymmetrical pair. These are flanked by the 
squamosals, which are somewhat longer and form the postero¬ 
lateral angles of the cranial roof. The frontals are very large, 
broad behind but attenuated in front; and the median suture 
between them is more or less wavy in its hinder portion. The 
postfrontal is exposed at the anterior end of the squamosal, and 
between it and the prefrontal there extends a series of about three 
supraorbital plates. The cheek is completely covered with thin 
