HISTORY. 19 



of his anatomical and physiological knowledge should have 

 overlooked the fact that secondary sexual characters are 

 developed in fishes as in any other class of animals, and that 

 fishes undergo great changes during growth; and, consequently, 

 that he described almost all such sexual forms and different 

 stages of growth under distinct specific and even generic names. 

 The system finally adopted by Cuvier is the following : — 



A. POISSONS OSSEUX. 



I. — A BRANCHIES EN PEIGNBS OU EN LAMES. 



1. A MACHOIRE SUPiRIEURE LIBRE. 



a. Acanthopterygiens. 



Percoides. Sparoides. Branchies labyrinthiques, 



Polynemes. Ch^todono'ides. Lophio'ides. 



MuUes. Scomber oides. Gobioides. 



Joues cuirass^es. Muges. Labroides. 

 Scienoides. 



b. Malacopterygiens. 

 Abdominaux. Subbrachiens. Apodes. 

 Cypriaoides. Sparoides. Murenoides. 

 SUuroides. Pleuronectes. 

 Salmonoides. Discoboles. 



Clupeoides. 

 Lucioides. 



2. A mIcHOIRE SUPilRIEURE FIXEE. 



Sclerodermas. Gymnodontes. 



II. A BRANCHIES EN FORME DE HOUPPES. 



Lophobranches. 



B. CaRTILAGINBUX OU CnONDROPTilRYGIENS. 



Sturioniens. Plagiostomes. Cyclostomes. 



We have to compare this system with that of Linnaeus 

 if we wish to measure the gigantic stride Ichthyology has 

 made during the intervening period of seventy years. The 

 various characters employed for classification have been ex- 



