THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



[FOURTH SERIES.] 

 No. 88. APRIL 1875. 



XXX. — On the Structure and Systematic Position of the 

 Genus Cheirolepis. By E. H. Traquair, M.D., F.G.S., 

 Keeper of the Natural-History Collections in the Edin- 

 burgh Museum of Science and Art. 



[Plate XVII.] 



This very interesting genus of Devonian fishes was originally 

 described by the late Prof. Agassiz, in the second volume of 

 his ' Poissons Fossiles,' p. 178, and was then included by 

 him in his family of '^ Lepidoides." The first step towards the 

 breaking-up of that heterogeneous assemblage was taken by 

 Agassiz himself, in the course of the publication of the same 

 great work, when he constituted the family of Acanthodidje 

 for the genera Cheir acanthus^ Acanfhodes, and Cheirolepis] 

 and this classification was retained in his special work on the 

 Fossil Fishes of the Old Red Sandstone, The founder of 

 fossil ichthyology seems, however, to have had but a slight 

 and not very correct conception of the structure of the fishes 

 with which he associated Cheirolepis, as may be seen both 

 from his restored figures and his remark that, as the bones 

 which he had been able to distinguish in Cheirolepis, '' such 

 as the frontal, humerus, temporal, have the same structure 

 as in ordinary osseous fishes," one may conclude " that the 

 Acanthodians in general had a complete osseous system, and 

 not merely a chorda doi-salis as in the Coccostei and other 

 fishes of the same epoch"*. Subsequent investigations into 



* Poissons Fossiles du vieux Gres Rouge, p. 44. 

 Ann. d:Mag. N. Hist. Ser. 4. Vol. xv. 17 



