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 PEIGNES OU EN LAMES, 



1. A MACHOIRE SUP^RIEURE LIBRE. 



a. Acanthopterygiens. 



Percoides. Sparoides. Branchies labyrinthiques, 



Polynemes. Chetodonoides. Lophioides. 



Mulles. Scomberoides. Gobioides. 



Joues cuirass^es. Muges. Labroides. 

 Scienoides. 



b. Malacopterygiens. 

 Abdominaux. Suhbrachiens. Apodes. 

 Cyprinoides, Sparoides. Murenoides. 

 Siluroides. Pleuronectes. 

 Salmonoides. Discoboles. 



Clupeoides. 

 Lucioides. 



2. A MACHOIRE SLTIiRIEURE FIXEE. 



Scl^rodermes. Gymnodontes. 



II. A BRANCHIES EN FORME DE HOUPPES. 



Lophobranches. 



B. Cartilagineux ou Chondropt]6rygiens. 

 Sturioniens. Plagiostomes. Cyclostomes. 



We have to compare this system with that of Linnseus 

 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- 



