Volume XL May, iSg^. Number I. 



JOURNAL 



OF 



MORPHOLOGY. 



THE EARLY DEVELOPMENT OF GAR-PIKE AND 



STURGEON. 



BASHFORD DEAN, 

 Columbia College, New York City. 



A MORE PERFECT KNOWLEDGE of the development of the 

 Ganoids seems to be especially needed to enable the relations 

 of the Teleostomes to be better understood. The study of 

 fossils has at the present time given the materials for the 

 better understanding of many important questions ^ relating to 

 the descent of fishes, but its results must yet conform with 

 those of the embryologist. It is thus especially unfortunate 

 that the development of Polypterus is at present totally un- 

 known, and that the study of even the more accessible forms, 

 Amia and Polyodon, has as yet been neglected. Indeed, of 

 those Ganoids which have hitherto been studied, the develop- 

 mental history seems to have presented so many difficulties to 

 observers that many years must go by before it may be satis- 



1 As for example, the relations of early Teleostomes to a stem essentially Elas- 

 mobranchian ; the descent of Mesozoic types of Ganoids from Crossopterygians; 

 the lines of ganoidean specialization ; the evolution of Sturgeon from palaeoni- 

 scoid ; the affinities of physostome and caturid. 



