290 M. Agassiz on the Scales of Fishes. 



thickness in these teeth at their hase and apex ; and that, in 

 reality, the points which beset the posterior edge of the scales 

 of the fishes, which 1 have named Ctemides, are simply the 

 more or less deeply marked notches of the edge, and not de- 

 tached teeth. 



Finally, M. INIandl seems to be completely ignorant, that 

 enamelled scales exist, which very sensibly differ in their struc- 

 ture from those of ordinary fishes, and which are to be found 

 in an order having the greater part of the species extinct, 

 which I have named Garoides. Neither has he paid much 

 attention to the examination of the shagreen of the Chon- 

 dropterygians, which form my order of Placoides. 



I shall enter into no farther details on the structure of the 

 scales of fishes, but merely conclude from my recent observations, 

 that the description I formerly gave of them is correct, and that M. 

 MandVs mode of regarding them is in every respect erroneous. 



With regard to the application I have made of the study of 

 scales to the classification of fishes, M. ]\'Iandl rightly blames 

 me for one error. When I described the Mullets as Cycloides, 

 I possessed nothing but the scales of a single individual from 

 Brazil, very ill-preserved, the small teeth, at their hinder edge, 

 being completely removed by friction ; but a new examination 

 of many species of this genus has convinced me, that the Mul- 

 lets are true Ctenoides, as M. Mandl has pointed out. 



M. Mandl terminates his memoir by atfii'ming, that I have 

 united in the same family, fishes possessing scales of very dif- 

 ferent structure. To answer this assertion, I shall simply re- 

 fer to the example cited by M. Mandl, viz. Cobitis, which I 

 place, in common with all modern ichthyologists, in the fami- 

 ly of the Cyprini. One may easily be convinced, by compar- 

 ing the scales of Cobitis with those of Gobio, Bar bus, and even 

 with those of the Carps properly so called (provided we ob- 

 serve the young scales before their surface has been altered) 

 that they present exactly the same structure : that is to say, 

 they are formed of plates with simple edges, as among all 

 my Cycloides, and that, consequently, the charge of inaccuracy 

 made against me falls to the ground. 



I would have addressed these refutations to the Academy 

 earlier, had I not been desirous, before doing so, of completely 



