174 GANOID FISHES OF THE CARBONIFEROUS FORMATION. 



area. For the most part the posterior margins of all the scales are even and entire, 

 denticulations being only occasionally, and indeed rarely visible. 



The pectoral fin is shown in one specimen ; it is small and composed of numerous 

 delicate rays which seem to be jointed for a considerable part of their length. I have 

 not seen the ventral in any specimen which I have examined. The dorsal is situated far 

 back so as to be situated nearly opposite the anal; both tins are short-based, triangular- 

 acuminate in shape, and are composed of delicate, brilliantly ganoid and distantly 

 articulated rays. The caudal is very heterocercal, deeply cleft and inequilobate, the 

 upper lobe being about twice the length of the lower, and nearly equalling one-third 

 of the entire length of the fish ; its delicate rays are similar in character to those of the 

 dorsal and anal. Delicate fulcra are visible on the anterior margins of all the fins. 



Geological Position and Locality. — Not uncommon in the fish-bearing beds of 

 Calciferous Sandstone age (Lower Carboniferous) exposed in the banks of the River Esk 

 near Glencartholm. 



2. Canobius elegantulus, Traquair. Plate XXXIX, figs. 4 — 6. 



Canobius elegantulus, Traquair. Trans. Boy. Soc. Ediub., vol. xxx, 1881, p. 47, 



pi. v, figs. 1 — 4. 

 — — A. S. Woodward. Cat. Foss. Fishes Brit. Mus., pt. ii, 



1891, p. 431. 



Specif 'c Characters. — Like C. Ranisayi in general form and dimensions ; flank-scales 

 having the greater part of the exposed surface sculptured with five or six prominent 

 straight ridges running across the scale in a direction nearly parallel with the upper and 

 lower margins, and ending in sharp points on the posterior margin. A median row of 

 specially large imbricating scales extends from the occiput to the origin of the dorsal fin. 



Description. — Length from 2 to 2| inches ; length of head contained nearly five 

 times, the greatest depth of the body about three and a half times in the total. Shape 

 shortly fusiform, rapidly tapering towards the tail, the upper lobe of the caudal fin being 

 elongated. The head is short and deep. 



The cranial roof-bones, which are Palaeoniscid in form and arrangement, are marked 

 externally with tolerably sharp, tortuous, and often reticulating ridges. The direction 

 of the suspensorium is nearly vertical, the posterior margin of the opercular flap evenly 

 rounded. The operculum is a quadrate plate with rounded-off postero-superior angle, 

 but its lower margin is not quite so oblique as in the last-described species ; it is 

 succeeded below by a suboperculum of nearly the same size, but having its postero- 

 inferior angle correspondingly rounded off. The preoperculum is very difficult of 

 detection, but seems to me to be represented by a very narrow plate in front of the 

 operculum and suboperculum. In front of this there is, instead of the one long vertical 

 suborbital, which we saw in C. Ranisayi, a chain of three or four short ones, in front 



