PHOLIDOPHORUS. 109 



feebly but coarsely rugose. So far as can be observed in other specimens, the 

 cheek-plates, mandible, and opercular bones are for the most part smooth, but bear 

 occasional prominent tubercles. The cheek-plates seem to be arranged as ordi- 

 narily in Pholidophorus, but they are often much broken by crushing (as in the 

 original of PL XXII, fig. 3). The large orbit as usual is crossed by a very stout 

 parasphenoid bone ; and an inner bone of the mouth, perhaps the vomer, bears a 

 few stout conical teeth. The mandibular suspensorium is inclined forwards below, 

 so that the quadrate articulation is beneath the hinder half of the orbit. The 

 maxilla is gently arched, with comparatively small teeth. About half the length 

 of the mandibular ramus is occupied by its elevated coronoid portion. 



As shown in the type specimen (PI. XXII, fig. l,pop.) the narrow preoperculum 

 is gently curved forwards below and not much expanded at the angle, where it is 

 grooved and pitted by the slime-canal but otherwise smooth. As shown from 

 within in PI. XXII, fig. 3, the suboperculum (sop.) is scarcely half as deep as the 

 operculum (op.), while the interoperculum (iop.) is large, long, and narrow. The 

 branchiostegal rays are short and broad ; and there seems to be a long and narrow 

 gular plate in the specimen figured by Davies (1887, pi. x, fig. 2), though this 

 interpretation is not certain. 



The axial skeleton of the trunk is always more or less obscured by the 

 squamation, but a close series of vertebral centra in the form of delicate ossified 

 cylinders is seen in side-view in B.M. no. P. 8379, and an isolated centrum occurs 

 in end-view in the same specimen. Traces of similar centra and short delicate 

 ribs are also seen in the original of PI. XXII, fig. 2. 



In the pectoral arch the supraclavicle (PI. XXII, fig. 1, scl.) is about three 

 times as deep as broad, with the outer face and hinder margin smooth. The 

 narrow exposed portion of the clavicle is marked by longitudinal ridges or plica- 

 tions. Two postclavicular scales are clearly seen above the pectoral fin both in 

 the original of PI. XXII, fig. 3, and in B.M. no. 40635, the lower being about as 

 broad as deep, the upper much deeper than broad, and tapering upwards. In the 

 pectoral fin (PI. XXII, fig. 2) the foremost ray is much stouter than the others, 

 and seems to have borne large fulcra. The pelvic fins are not much smaller than 

 the pectorals, and their foremost ray bears at least six large and deeply overlapping 

 smooth fulcra, which extend nearly to its distal end. The dorsal and anal fins, 

 the former just in advance of the latter, are similar in size and shape, each with 

 about ten divided rays, which rapidly decrease in length backwards, and of which 

 the foremost is fringed nearly to the end with eight or nine large and deeply 

 overlapping smooth fulcra. The relatively large forked caudal fin, with nearly 

 twenty rays, is similarly fulcrated, but the dozen fulcra above and below rapidly 

 decrease in size distally and do not reach the extremity of the foremost ray. 

 In all the fin-rays the segments between the articulations are somewhat longer 

 than broad. 



