70 GANOID FISHES OF THE CARBONIFEROUS FORMATION. 



Ehnichfhys, I own that I long ago ceased to consider it a character of sufficient impor- 

 tance to be diagnostic of a species, seeing that in other respects the specimen showing it 

 is essentially inseparable from the series of forms which I have felt compelled to associate 

 together under Elonichthys Robisoni of Hibbert. Accordingly in 1890 I also reduced 

 E. Dtmsii to the rank of a variety. 



5. Elonichthys serratus, Traqiiair. Plate XII, figs. 5 — 8. 



Elonichthys serratus, Traquair. Trans. Koy. Soc. Edinb., vol. xxx, 1881, 



p. 22, pi. i, figs. 5—8. 

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



1891, p. 499. 



Specific Characters. — Attaining a length of four inches and a half; shape elegantly 

 fusiform and somewhat slender ; scales j)roportionally small, those of the flank showing 

 posteriorly five or six coarse oblique ridges terminating on similarly coarse oblique 

 denticulations of the hinder margin, below which are a few finer ridges parallel with the 

 convex lower margin of the scale ; fins relatively small ; principal rays of pectoral articu- 

 lated up to their origins ; rays of median fins slender, their joints much longer than 

 broad, smooth or only with very scant striation. 



Description. — The largest specimen I have seen is four and a half inches in length, 

 but the general pro[)orti()ns are best seen in the one represented on PI. XII, fig. 5, 

 which measures only three and three quarters. 



The cranial roof bones are somewhat coarsely tuberculated, the tubercles tending to 

 become elongated and sometimes confluent; while as to the facial bones, so far as their 

 outer surfaces can be seen their sculpture seems to consist of somewhat tortuous ridges. 

 The scales are relatively small ; those of the flank (fig. 6) are higher than broad, and have 

 the upper margin concave, the lower convex in outline. Passing over the posterior two 

 thirds of the exposed surface are five or six coarse oblique ridges, which end on the same 

 number of prominent denticulations of the hinder margin, a small space below being 

 occupied by several finer ridges parallel with the rounded lower margin. In some speci- 

 mens a few delicate striations are also to be seen in front of and among the coarse ridges 

 already described. Posteriorly (fig. 7), as the scales become smaller, the ridging and 

 striation become less prominent, the ornament becoming reduced to a few longitudinal 

 grooves and punctures, which finally disappear near the commencement of the caudal 

 fin, the denticulations of the posterior margin becoming likevnse fewer in number and 

 ultimately lost, the scales on the tail pedicle and caudal body-prolongation being 

 altogether smooth, with the exception of one or two punctures here and there. The 

 variations in the general shape of the scales on different parts of the body are in accord- 

 ance with what is found in other species of the genus. 



