290 
ACTINOPTERYGII. 
there is a large gular plate covering the whole of the space between 
the mandibular rami in front of them. 
The notochord is persistent, but there are usually some traces 
of hypocentra and pleurocentra, and these are often robust in the 
larger individuals. In the abdominal region there are slender ribs 
loosely articulated with short prominences on the hypocentra ; and 
there is the series of large free neural spines, so well known in 
Caturns, extending as far as the anterior portion of the dorsal fin. 
In the caudal region the neural and haemal arches are stout, and 
the haemal spines at the base of the caudal fin are somewhat 
expanded. 
A single pair of transversely extended supratemporal plates over¬ 
laps the occiput, and immediately behind is observed the exposed 
portion of a pair of large triangular post-temporals, which support 
the pectoral arch. The supraclavicle is long and narrow, and the 
arched clavicle is relatively very large. The latter element is 
contracted and thickened above, with a considerable outer lamina 
mesially, and tapering to a delicate point below where it meets its 
fellow of the opposite side. On its antero-superior angulation there 
are several longitudinal rugae. The scapula, coracoids, and hasals 
are not satisfactorily known ; but it is clear that the immediate 
supports of the pectoral fin-rays were much like those of Ophiopsis 
(p. 167, PI. III. fig. 3), the hindermost basal being the largest. 
The pelvic fin-supports are irregularly hourglass-shaped, much more 
expanded proximally than distally, arS shown in Caturus (PI. IX. 
fig. 3). Conspicuous biserial fulcra appear on all the fins. 
Thick rhombic ganoid scales cover the whole of the trunk, and 
are arranged in regular oblique series except immediately at the 
base of the caudal fin, where the last row is directly related to 
covering the base of the rays. Each scale is strengthened on its 
inner face with a vertical median rib ; and the principal flank-scales 
are also united by a peg-and-socket articulation. A series of four 
large postclavicular scales is connected with the clavicle. Xone of 
the ordinary scales, however, are enlarged either along the dorsal 
margin or in the region of the anus. The position of the latter 
close to the origin of the anal fin is indicated by coprolitic matter in 
no. 48006. Some of the ventral scales in the region of the pectoral 
fins are much subdivided. 
