CLASSIFICATION OF DEVONIAN FISHES. 



7 



" distant than in the foregoing species." Thus it is admitted that 

 GlyptoleiJis has not smjDoth, but sculptured scales, as, indeed, the 

 name of the genus implies. 



Agassiz enumerates a caudal, two dorsal, and two anal fins, but 

 states that the existence of pectorals is doubtful, and that, in any 

 case, they must have been small and inconsiderable. The ventral 

 tins, on the other hand, are said to possess a singular structure, 

 " which is also to be found in Megalichthys.'' A series of plates 

 extends as a pointed band along the belly, and, becoming free at its 

 posterior extremity, carries numerous rays on both sides, and thus 

 forms a ventral fin, which, from the manner in which its rays are 

 disposed, is very like an eels tail. (Tab. 21, fig. 2.) I have ex- 

 amined the specimen here referred to, which forms a part of Sir 

 Philip Egerton's collection, and, with Professor Pander, I feel satis- 

 fied that the fin in question is the very long, acutely lobate, pectoral, 

 bent back in such a manner, that the proxim^al half of its posterior 

 edge is covered by the lower margin of the abdomen of the fish. 



Professor Agassiz goes on to say that the two dorsals are opposed 

 to the two anals, and are situated so far back that the caudal 

 directly follows them. They are so close together that the last ray 

 of the first touches the first ray of the second. The second dorsal 

 and anal are higher than the first, and the caudal is large, hetero- 

 cercal, and triangular, appearing to be almost vertically truncated ; 

 its superior division bears numerous little fulcra. 



Hugh Miller Old Red Sandstone/' 1841,) made some important 

 improvements upon Agassiz' description and definition of Glyiitoleins 

 He pointed out with great justice (and figured a specimen demon- 

 strating the fact), that there is only one anal, the second, or posterior 

 of Agassiz, the ventrals having been mistaken for an anterior 

 anal, and he describes and gives a sketch of the sculptured outer 

 surface of the scales. 



Professor Pander, in the Monograph already cited, has carried the 

 work of rectification still further, though even he ventures upon no 

 restoration of GhjiJiolepis, seeming to be unacquainted with the 

 figure of the body of the fish, from a specimen more complete than 

 any of those of Agassiz, or of his own, given by Hugh Miller. 



In addition to what was already known, he states that the prin- 

 cipal jugular plates are separated, anteriorly, by a small rhombuidal 

 one, and he makes the observation that " these plates, which among 

 " living fishes occur double only in Polypterus, and are among fossils 

 " known only in OsteoUpis, Biploptenis, MegalicJithys^ and Gyropty- 

 " chius, lead to the supposition that the composition of the cranial 



and facial bones will differ in no important respect from, what is 



