Classification of Fishes. 



CLASSIFICATION OP FISHES. 



SUB-CLASS I. ELASMOBRANCHIL Jaw-apparatus" 

 suspended from skull ; no operculum ; dermal 

 armour without bone-tissue 



Order I. PBOSELACHII. Paired fins supported by 

 parallel rods of cartilage ; no claspers in 

 male 



Order II. ICHTHYOTOMI. Pectoral fins supported 

 by cartilages radiating from central axis ; 

 claspers in male 



Order III. ACANTHODII. Ail fins except caudal 

 with spine in front, and cartilages very 

 short ; no claspers 

 Order IV. SELACHII. Pectoral fins with two or 

 three basal cartilages and no central axis ; 

 claspers in male 



Sub-orders. Tectospondyli and Asterospondyli 

 SUB-CLASS II. HOLOCEPHALL Jaw-apparatus fused 

 with skull ; an opercular membrane ; dermal 

 armour without bone-tissue 



Order I. CHIM^EOIDEI. Fins as in Selachii ..J 

 SUB-CLASS III. DIPNOI. Jaw-apparatus fused witlT) 

 skull; an opercular bone; dermal armour | 

 often with bone-tissue . . . . . . 



Order I. SIBENOIDEI. Scaly fishes with paddle- 

 shaped paired fins, these supported by a j 

 segmented axis . . . . . . . . J 



Order II. AETHEODIEA. Armoured fishes, the ] 

 head-shield hinged on body-shield ; paired 

 fins rudimentary 



SUB-CLASS IV. TELEOSTOMI. Jaw-apparatus sus- 

 pended from skull ; an opercular bone ; dermal 

 armour often with bone-tissue 

 Order I. CEOSSOPTEEYGII. Paired fins paddle- 

 shaped and fringed with fin-rays 



Elasmobranchii 



or 

 ' Chondropterygii. 



Dipnoi. 



\> Granoidei. 



Sub-orders. Haplistia, Rhipidistia, Actinis- 



tia, and Cladistia 



Order II. ACTINOPTEETGII. Supports of paired 



fins much shortened and dermal rays 



chiefly supporting membrane 



Sub-orders. Chondrostei, Protospondyli, 



Aetheospondyli, Isospondyli (in part)J 



Isospondyli (continued), Plectospon-\ 



dyliy Nematognathi,Haplomi,Apodes, j 



Anacanthini, Percesoces, Pharyngo- j> Teleostei. 



gnathi, PercomorpM, Lophobranchii, \ 



HemibraneMi, and Plectognathi .. J 



