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Iiecherches sur les Poissons Fossiles. 



are almost every where found, as we may perceive from the 

 Tables A, &c. Vol. ii. Attention to the plates of the follow- 

 ing livraisons will afford still better examples of this 

 analogy.* We found again in many fishes peculiar ranges 

 of scales on the middle of the back or of the belly, at 

 the insertion of the fins extending vertically with the fin 

 rays.f 



From all the possible modifications in these different com- 

 binations, it follows, that there must be a very great variety 

 in the external aspect of scales ; yet they present always the 

 same organization, and may be all regarded as branches of 

 one fundamental type, whatever may be their apparent form, 

 or whether they are imbricated or not; whether they are 

 thin and formed only, some of small horny laminae, or thick 

 and at the same time osseous plates. It is very easy to 

 examine these analogies in all the modifications which they 

 present in the different families of the class, however numerous 

 and however varied they may be. It is not, however, my ob- 

 ject in this place to stop to describe all the forms which 

 exist. These details will be found in the following volumes 



* In examining attentively the plates of this work, (Recher dies sur les 

 Poissons Fossiles,) and comparing them with nature, my readers will be 

 convinced that in all the fishes which I have represented, the scales are 

 figured in their natural position, and with their characteristic form. I 

 have made this remark particularly, because the greater part of plates 

 which exist, are in gross violation in this respect, of laws the most 

 constant and precise. 



t The most remarkable instance of this peculiarity occurs in the 

 genus Schizothorax of Heckle, in which the lower ventral ranges of scales 

 separate some distance in front of the anal fin, leaving a naked mem- 

 branous space in which the outlet of the intestine is placed. The group 

 in which this peculiarity occurs belongs to the mountains of India, and 

 was unknown to M. Agassiz, at the time the above was written, 

 otherwise he would probably have thought it deserving of some special 

 notice. He will since have become acquainted with it, however, from 

 the work of M, Heckle on the fishes of Cashmere. — Ed. 



