Palaeontology. 337 



bryonique du r^gne des poissons." A part of the peculiar 

 structure which he especially dwells upon is, " le developpe- 

 ment extraordinaire que presente le systeme cutane ;" but he 

 acknowledges that " malheureusement nous n'avons pas en- 

 core des termes de coraparaison avec les poissons de la crea- 

 tion actuelle assez nombreux pour apprecier la valeur de ces 

 caracteres." Another feature of the peculiar structure which 

 he points out is the continuity of the vertical fins. This cha- 

 racter, however, Sir Philip Egerton and Professor Owen in- 

 form me, is only of partial application ; the family of Cepha- 

 laspides he does not cite, but in Coccosteus^ the sole form of 

 Old Red fishes in which vertical fins have been observed, the 

 distance between them is considerable. In the Dipterians, 

 Dipterus has these organs very close, but in Diplopterus and 

 Osteolepis they have considerable intervals between them. 

 Diplopterus^ moreover, occurs in the coal measures. In the 

 Coelacanths the fins of Glyptolepis are very near each other, but 

 this family runs into the chalk. In the Acanthodians the fins 

 are quite distinct, and Acanthodes is found in the coal measures. 

 There are also recent fishes with their vertical fins quite as 

 little distinct as in the most exaggerated of the Old Red. 

 Neither is the heterocerque tail a character peculiar to the 

 fishes of the Old Red, for all the fishes older than the lias have 

 this form, as have the Sturgeons of the present day ; and it 

 is perhaps more important to find, that certain highly charac- 

 teristic genera of the Old Red, for example, Pterichthys, 

 Pamphractus and Coccosteus^ did not possess the heterocercal 

 tail. 



Another character, viz., the flattened form of head, is not 

 peculiar to the Old Red, for the Siluridce and other recent 

 fishes have this character equally prominent. Then the non- 

 development of the vertebral column is found in the Sturgeon, 

 Lamprey, and other recent fishes. Persons seeking for sup- 

 port to the theory of progressive development might, on a 

 hasty perusal of this work, find sentences in favour of their 

 views ; but the above facts are irreconcilable with the theory 

 as ordinarily promulgated, and it would be a perversion of 

 M. Agassiz's undoubted opinions to quote detached sentences 

 from his writings in support of that doctrine. They will find 



