﻿30 GANOID FISHES OF THE CARBONIFEROUS FORMATION. 



2e Tribu. Lepidosteides homocerques a bouche et ecailles normales, a dents en 



brosse ou obtuses {Lepidotus, Pholidophorus, Centrolepis,\ &c.). 

 3e Tribu. Lepidosteides a bouche et ecailles normales et a dents crochues et isolees 



{Lepidosteus, Caturus, Eugnathus, Thrissonotus,\ &c.). 

 4e Tribu. Lepidosteides heterocerques a dents coniques isolees (Saurichthys, Mega- 



lichthys, Pggopterus,f Acrolepis t) . 

 5e Tribu. Lepidosteides heterocerques a dents en brosse ou obtuses {Amblypterus,\ 



Eurynotus, Elonichthys,\ Palaoniscus,\ Urosthenes,\ Catopterus)} 



Cheirolepis remains an Acanthodian. 



The subdivisions of the order Ganoidei proposed by Professor Huxley in his celebrated 

 ' Essay on the Systematic Arrangement of the Fishes of the Devonian Epoch/ which 

 was issued in 1861, are as below : 



I. Amiudce. 

 II. Lepidosteida. 



III. Crossopterygidce. 



IV. Chondrosteida. 

 V. Acanthodidce. 



As regards the second sub-order, the Lepidosteida, only the following provisional 

 sketch of an arrangement was given : 2 



" Lepidosteidse. Heterocercal Ganoid with rhomboidal scales, branchiostegal rays, 

 non-lobate paired fins, a preoperculum and an interoperculum. 



" Fam. 1. Lepidosteini. "Maxilla divided into many pieces, branchiostegal rays 

 few and not enamelled. 



" Lepidosteus. 



"Fam. 2. Lepidotini. "Maxilla in one piece; branchiostegal rays many and 

 enamelled, the anterior ones taking the form of broad plates. 



" (a). jEchmodus, Tetragonolepis, Dapedius, Lepidotus, &c. 



"(6). Eugnathus, Pachycormus, Oxygnathus, &c. 



" (c). AspidorJiynchus. 

 " Perhaps the genera marked a, b, c should form distinct sub-families." 



Palaoniscus is not here specially referred to, but in sub-family b of the family 

 Lepidotini Oxygnathus, a prominent member of the Palceoniscidce, is placed along with 

 the rather dissimilar genera Eugnathus and Pachycormus. At the end of the essay, how- 



1 Those genera in the above list, to which a f is appended, are included in the family of Palceoniscidce, 

 as described and defined in the present work. 



2 'Dec. Geol. Survey,' x (1861), p. 28, footnote. 



