﻿ELONICHTHYS CAUDALIS. 



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2. Elonichthys caudalis, Traquair, sp. nov. Plate V, figs. 1 — 4. 



Of this I have only seen one specimen, the counterpart of which, being the more 

 perfect side of the fossil, is represented in PI. V. It is also from the Knowles Ironstone 

 of Fenton, North Staffordshire; and, though smaller, seems to have resembled the 

 preceding Fish very much in shape. The sculpture of the scales, however, is rather 

 different. 



Description. — The length of the specimen from the posterior margin of the gill-cover 

 to the bifurcation of the caudal is 5^ inches ; to opposite the apparent end of the upper 

 lobe Q\ inches. Its greatest breadth at the front of the dorsal fin may be given at 

 2-| inches. The head is, at its junction with the body, bent over to the left side at so 

 considerable an angle that it was impossible to represent it in the drawing of the entire 

 Fish, and a detached figure of the impressions of its bones has therefore been given 

 (PI. V, fig. 2). The anterior part of the head is lost ; but the external bones, posterior to 

 the orbit, are recognisable, though only in impression of their outer surfaces ; a little of the 

 bone, however, adhering here and there to the matrix. Judging from these impressions, 

 it is evident that the suspensorium was very oblique, the operculum {op.) long and 

 narrow, the interoperculum quadrate, the maxilla [mx.) of the usual form, broad behind 

 and excavated or cut out above just behind the orbit. Along the upper margin of the 

 maxilla, and in front of the operculum, is seen the impression of the upper acutely trian- 

 gular portion of the praeoperculum [p. op.), in front of which are some obscure remains 

 of the broad outer suborbital plates (s. o). The gape, of course, extended very far back: 

 only a very narrow portion of the impression of the upper margin of the mandible is 

 seen bounding the mouth below, with some feeble traces of sharp conical teeth ; behind 

 the angle of the mouth are also seen the remains of the first two branchiostegal rays. 

 Above the operculum and praeoperculum is the concave impression of the posterior part 

 of the cranial shield, showing very obscurely the parietal and squamosal plates. Behind 

 this, at the upper and back part of the head, is seen the inner surface of the post-temporal 

 {p. t.), a small rounded- trigonal plate, extending from which, obliquely downwards and 

 backwards behind the operculum, is the impression of the supra-clavicular (s. cl.). The 

 ornament of the outer surface of the cranial buckler is, as far as can be made out, of a 

 tubercular character ; that of the facial bones, on the other hand, consisting of delicate 

 branching and anastomosing wavy ridges or striae. 



The disturbed aspect of the scales immediately behind the head would lead us to 

 believe that the anterior part of the specimen has been somewhat shortened by distortion, 

 the head being pushed backwards on the body ; and in this manner the apparently 

 abnormally anterior position of the dorsal fin, and the seeming disproportion between 

 the caudal and abdominal portions of the Fish, may be accounted for. On the inferior 



