122 GANOID FISHES OF THE CARBONIFEROUS FORMATION. 
measuring from about 34 to 44 inches in length; the exception is formed by the head 
and fore part of the body of an individual which must have, when entire, measured at 
least 6 or 7 inches. ‘The general form is elegant and slender ; the greatest depth is at 
the shoulders, whence the body gradually tapers towards the caudal extremity. ‘Taking 
into account the phenomena of ‘shortening up” and “lengthening out,” so common 
among Paleozoic fossil fishes, the head would occupy about one fifth of the total length, 
while the ventrals would be situated at rather less than two fifths, and the beginning of 
the dorsal and anal fins at less than three fifths from the tip of the snout. 
The osteology of the head is typically Paleeoniscid, with oblique suspensorium, wide 
gape, and prominent superethmoidal prominence. ‘The external surfaces of the bones of 
the cranial roof seem to have been finely tuberculated, the tubercles being sometimes 
confluent into short ridges. In one specimen a good view of the hyomandibular element 
pt ym POP 
fhm 
B 
Fig. 5.—a. Sketch of the side of the head with the bones of the face and shoulder of Cycloptychius carbonarius, 
somewhat enlarged and restored. Op., operculum; p.op., preoperculum; s.op., suboperculum ; s.0., suborbital ; 
ma., maxillary; mn., mandible; h.m., hyomandibular; 67., branchiostegal rays; p.f., post-temporal; s.c/., 
supra-clavicular; cZ., clavicle; p.cl., post-clavicular ; z.cl., infra-clavicular. 8B. Isolated hyomandibular bone of 
Cycloptychius carbonarius. _ Magnified slightly. 
is obtained. It is a somewhat long-shaped bone (‘Text-fig. 58), which descends 
obliquely downwards and backwards towards the articulation of the lower jaw, and is 
compressed laterally, while below the middle it is slightly bent forwards again at a low 
angle ; iz situ the upper part is very oblique, the lower nearly perpendicular. ‘The orbit 
is, as usual, placed far forwards and surrounded by a chain of ossicles whose exact 
number can scarcely be determined. The maxillary bone is stout and broad till it comes 
to the orbit, where, as in other Paleoniscide, it is suddenly cut away, the anterior 
extremity passing on below the eye in a pointed process towards the premaxillary. The 
operculum is rather narrow, though broader above than below ; the suboperculum is 
small and quadrate in shape; the branchiostegal rays or plates are numerous. The 
mandible, whose separate elements it is impossible to define, is stout in its posterior half, 
but tapers nearly to a point anteriorly. 
‘The teeth, with which the margins of both jaws are armed, are of the usual type, being 
2) 
conical, sharp, slightly incurved, and enamel-capped. They are of two sizes—Jarge 
