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GANOID FISHES OP THE CARBONIFEROUS FORMATION. 



shape, but with the lower margin longest, and the postero-inferior angle rather acute ; 

 as in most Palaoniscida, I see no trace of suboperculum. Above the operculum is seen 

 the somewhat displaced post-temporal ; while below and in front is a portion of the 

 maxilla, which bone being broken off behind, the hard palate comes partly into view 

 between it and the opercular bones. On turning the specimen round, both rami of 

 the lower jaw are seen, along with the rest of the branchiostegal rays. Each ramus, 

 strong, though tapering, measures nearly three inches in length from its articular to its 

 symphysial extremity ; external to the right one is seen a portion of the margin of the 

 right maxilla, with no less than six laniary teeth in the space of half an inch ; there are 

 also traces of some of the smaller teeth. The left series of branchiostegal rays is trace- 

 able from beneath the interoperculum, round between the rami of the mandible, where 

 they come in contact internally with the series of the other side (PI. Ill, fig. 9). The 

 number of these plates is unusually large, there being at least twenty-two on each side ; 

 they are imbricating in arrangement and narrow in form, save the anterior of each lateral 

 series, which is much broader than the rest ; while there is also clear evidence of a 

 median lozenge-shaped plate just behind the symphysis. 



As regards the external ornament of the cranial bones, the lower jaw is sculptured 

 externally with fine, wavy, branching and anastomosing, longitudinal ridges, passing 

 near the dental margin into a fine tuberculation ; some obscure remains of the bone of 

 the top of the head are seen in the front of the specimen, on which the ornament is 

 apparently tubercular. On all the other bones visible it is of a finely ridged or striated 

 character. The scales visible behind the head in this specimen are not very well 

 preserved, but the nature of their sculpture, where visible, proves that the head belongs 

 to the same species as that to which the other specimens are referable. The other head 

 (No. 9), belonging to Mr. Ward, and likewise crushed vertically, does not exhibit so 

 many details as the one just described, with which, however, it agrees in all essential 

 points. 



Observations. — This is the largest species of Elonichthys known, except a somewhat 

 doubtful form from the lower strata of the Scottish Coal-fields, known as yet only by 

 detached scales and a portion of a jaw, and to which I shall further on give the name of 

 E. pectinatus. The peculiar sculpture of the scales, its deep and massive body, and the 

 enormous size of its fins, readily distinguish Elonicldhys semistriatus from all the other 

 species of the genus, though in many respects, as in the conformation of the fin-rays, the 

 configuration and external markings of the cranial bones, and the dentition, it is also 

 closely allied to the two species next to be described from the same horizon and locality, 

 viz. E. caudalis and E. oblongus. 



Geological Position and Locality. — The specimens above described are all from the 

 Coal-measures, and were found in the " Knowles Ironstone " and accompanying shale of 

 Fenton, North Staffordshire. I have also reason to believe in its occurrence in the Coal- 

 strata of Northumberland. 



