326 Prof. Agassiz on Fossil Fishes. 



Buckland, of the Rev. Mr Hope, of Messrs Bowerbank, Cum- 

 berland, the Directors of the British Museum, of the College 

 of Surgeons, &c., who have all eagerly communicated to me 

 the original fragments from their collections, which I have 

 thus been able to compare directly with the crania of recent 

 fish. This investigation has thus been made on entirely new 

 bases. The labours of former ichthyologists have scarcely af- 

 forded the least assistance ; and even the gi-eat works on Com- 

 parative Anatomy of Cuvier, Meckel, and so many others, have 

 rarely furnished sufficient information ; for their object is, to 

 make known the bones of the cranium and of the head in 

 general, to indicate the part which these bones take in the 

 formation of the osseous skeleton of the head, to describe the 

 variations they may undergo in composing the most extrava- 

 gant types, and, lastly, to point out the analogy of the bones 

 with those of other classes of Vertebrata, rather than to indi- 

 cate the precise form of each bone in all the genera. The 

 same is the case with respect to the great anatomical discus- 

 sions at the commencement of the present century, which re- 

 lated to the analogy of the head of fish with that of the other 

 Vertebrata, rather than to the details necessary for the deter- 

 mination of fossil bones. 



The object which I proposed to attain in these new researches 

 on the osteology of fish, was, above all, to become acquainted 

 with the forms of the head and of the cranium, to determine 

 their ridges, the hollows, and the relief in all their details, 

 and to find in these different forms general types of the family, 

 of the genus, and of the species. If my predecessors have 

 fixed on a regular type, the Carp or Perch, in describing their 

 osteology, and in pointing out how these types may vary in 

 the irregular genera, I, on the contrary, have had to direct my 

 attention principally to closely-allied types, to search for the 

 minute deviations which might accompany specific differences, 

 to study the general character of the genus, to indicate the 

 variations which the still more general type of the family 

 might be subject, and thus to arrive at the possibility of dis- 

 tinguishing families, genera, and species by the osteology of 

 the cranium. It will be conceived that this study is almost 

 interminable ; for — and this is a new manifestation of the in- 



