78 GANOID FISHES OF THF CARBONIFEROUS FORMATION. 



Elonichtuxs Aitkeni, Wa7-d. Trans. N. Staffs Inst. Mining Engin., 1890, 



p. 174, pi. vi, figs. 9—12. 



— — A. 8. WoodicarJ. Cat. Foss. Fishes Brit. Mus., pt. ii, 



1891, p. 490. 



— — Wellburn. Proc. Yorks. Greol. and Polyt. Soc, vol. xiii, 



1898, p. 398 ; ibid., p. 426, pi. Ixii, tig. 5. 



Specific Characters. — Length G to 7 inches. Scales of moderate size, ornamented 

 by strongly marked ridges, which on the anterior flank scales run diagonally over the 

 surface from above downwards and backwards, but over the greater part of the body are 

 parallel or nearly so with the upper and lower margins of the scale; posterior border 

 denticulated. Principal rays of pectoral fin unarticulated for abont one third of their 

 length ; rays of median fins dehcate, distantly articulated, smooth, or it may be with 

 only one feebly marked longitudinal farrow. 



Bescripiion . — The shape is fusiform and moderately deep. The cranial roof bones 

 are sculptured with undulating ridges, passing at times into elongated tubercles. The 

 mandible (PI. XVII, fig. 5) is sculptured externally with slightly wavy longitudinal 

 ridges, which run tolerably parallel with the upper and lower margins of the jaw, but the 

 dentary margin is finely tuberculated. The maxilla (fig. 4) is of the usual form; its 

 dentary margin is also tuberculated, while the rest of the surface is covered by 

 undulating ridges disposed in a manner more or less parallel with the upper and 

 [)Osterior margins of the broad portion forming the mass of the bone, but passing 

 longitudinally along the narrow portion in front. In both jaws the teeth are conical, 

 strong and sharp, and of two sizes, larger and smaller. The operculum is ornamented 

 with ridges which pass obliquely over the surface from above downwards and back- 

 wards, while those on the suboperculum are more transverse in their direction. 



The scales are of moderate size. Those of the flank are higher than broad, but 

 conforming to the general rule they become more oblique and equilateral posteriorly, and 

 towards the dorsal and ventral margins they become rather lower than they are broad. 

 Their ornament consists of sharp, strongly marked ridges, occasionally bifurcating or 

 intercalated, which in the case of the flank scales (fig. 2) run rather diagonally over the 

 surface from above downwards and backwards, but over the greater part of the body are 

 parallel with the u[)per and lower margins (fig. 3) ; and seldom does any greater 

 obliquity of the ridges on the anterior and lower part of the scale give any indication of 

 the diagonal division of the pattern which is so common in striated scales of the family 

 Palaeoniscidae. Posteriorly a peculiar and highly ornamental character is given to the 

 squamation by the fact that the lowermost ridge (see fig. 3), uniting or not with the one 

 next above it, is of unusual breadth, and stands prominently out. On the V-shaped 

 ridge-scales of the caudal body-prolongation the ornament becomes speedily obsolete, and 

 the small lozenge-shaped lateral scales are at most marked by one or two slight 

 longitudinal furrows. 



