364 MEMOIRS OF THE CARNEGIE MUSEUM. 



Genus Histionotus Egerton. . 

 " Head large, snout acute; the dorsal margin of the trunk rising above the head 

 to an angulation from which the body gradually tapers backwards. Marginal 

 teeth much elongated, closely arranged. Notochord invested with delicate ring- 

 vertebrae. Fins consisting of distally bifurcating rays, all with large A-shaped 

 fulcra; pectoral fins much larger than the pelvic pair; dorsal fin arising at the angu- 

 lation of the back, extending to the caudal pedicle, high in front, becoming low 

 behind; anal fin small; caudal fin forked. Scales covering the whole of the trunk, 

 in regular series, united by peg-and-socket articulation, and more or less pectinated 

 at the hinder border; [the scales of the middle of the flank and of the dorsal region 

 much deeper than broad, with more or less convex hinder border — Eastman] ; those of 

 the ventral region at least as broad as deep ; postclavicular scales very large ; the 

 ridge scales of the caudal pedicle not much enlarged." (A. S. Woodward, I. c, 

 Pt. Ill, pp. 173-4). 



8. Histionotus falsani ThioUiere. (Plate XLIX, fig. 1). 

 1873. Histionotus falsani ThioUiere. 



Poiss. Foss. Bugey, Pt. II, p. 14; pi. V, fig. 1. 

 1895. Histionotus falsani A. S. Woodward. 



Cat. Foss. Fishes Brit. Mus., Pt. Ill, p. 175. 



Type. — Much fractured fish; Lyons Museum. 



A species about equalling the type of the genus in size, but the maximum depth 

 of the trunk somewhat exceeding half its length, and the head with opercular 

 apparatus at least as deep as long. Marginal teeth strong and conical, closely 

 crowded. Fulcra prominent on all the fins; scales delicately pectinated along their 

 posterior border. 



This species was at first regarded by the original author as identical with 

 H. angularis Egerton from the Purbeck of Dorset and Wiltshire. It differs from 

 the latter form, however, and also from H. oberndorferi of Wagner, in the less 

 acute angulation of the back, less rapidly tapering posterior region of the trunk, and 

 less coarsely serrated character of the scales. 



A single representative of this species, preserved in the collection of the 

 Carnegie Museum, is shown in the plate and is No. 4077. It is nearly as large as 

 the type of the genus, and presents the appearance of having a discontinuous dorsal 

 fin. The resemblance to Histionotus in other respects, however, is too close to 

 permit us to doubt that it is properly referred to this genus. 



