96 GANOID FISHES OF THE CARBONIFEROUS FORMATION. 



while the spine and its socket diminish and ultimately disappear. The posterior 

 margin of the scale is finely and obliquely serrated. On the outer surface the margin 

 overlapped by the scale next in front is very narrow ; the exposed area is, in the most 

 anteriorly situated scales, ornamented with delicate and rather feebly marked striae, best 

 marked along the anterior and inferior margins, with which they run parallel, and 

 usually becoming speedily obsolete over the rest of the scale, so as to leave a consider- 

 able space above and behind, marked only with tolerably coarse punctures (fig. 7), 

 though in many cases (fig. 5) shallow grooves also extend for some distance forwards 

 from the notches between the denticnlations of the posterior border. These striae are 

 much more pronounced in some specimens than in others, except on the small scales at 

 the base of the dorsal fin, where they are pretty well marked; they cease to be 

 observable before the origin of the ventrals, whence backwards the only scale ornament 

 consists of scattered punctures passing into short oblique furrows, especially near the 

 inner margin, these punctures and furrows being persistent even on the small lozcnge- 

 shapecl scales clothing the sides of the caudal body prolongation. The scales also vary 

 considerably in size on different parts of the body, becoming rapidly smaller posteriorly, 

 and those immediately below and adjoining the base of the dorsal fin are of 

 particularly small size. The rest of the squamation presents nothing specially worthy 

 of note. 



The pectoral fins are acutely pointed and of considerable expanse ; the length of each 

 is equal to about three quarters that of the head. The ventrals are smaller, short-based, 

 and have their posterior margins rather concavely cut out. The dorsal is placed behind 

 the middle of the back, so that the centre of its base is nearly opposite the commence- 

 ment of the anal ; both these fins are large and triangular-acuminate ; the caudal is 

 powerful and deeply cleft. The rays of all the fins are very numerous and delicate ; 

 their number in the pectoral cannot be less than thirty; in the ventral twenty-three; in 

 the dorsal and anal forty-five each ; those of the caudal cannot be counted. The 

 articulations of the fin-rays are also tolerably close, especially in the finer rays of the 

 posterior part of each fin, where the joints appear nearly square, being in the other rays 

 rather longer than broad ; the articulations are more than usually distant towards the 

 proximal extremities of the principal rays of the pectoral, and also, though to a less 

 extent, in the lower lobe of the caudal. The joints are scale-lilce in general aspect ; 

 the distal margin of each is notched or concave, the proximal correspondingly convex ; 

 and the outer surface is in most cases marked with at least one delicate furrow parallel 

 with the anterior and posterior borders; near the bases of the dorsal and anal fins the 

 joints present, indeed, an appearance of fine striation. The fulcra of the anterior 

 margins are closely set and very minute. 



Observations. — The salient characters which distinguish this, the type species of the 

 genus, from the two following, are the shape of the maxilla and the moderate size of the 

 teeth. The scales are also comparatively moderate in size, and tend to display, at least 



