176 OUTLINES OF ICHTHYOLOGY. 



tutes the upper jaw — in other words, the jaw-bones being sol- 

 dered together. 

 Two FamiHes. 



The CARTILAGINOUS FISH, or CHON- 

 DROPTERYGII (from the Greek chondros, 

 cartilage, and pterygion, a fin), consisting of two 

 Orders, viz. : — 



ORDER I. 



Chondropterygii BranchiisLiberis, or CaiUlaginoiis Fish 

 with free gills. (From Latin hranchia, gills, and liber, free.) — 

 The Fish forming this Order have a single wide opening in their 

 gills, and a gill-cover as in the Bony Fish ; but no gill-rays. 



The Order contains two Families. 



ORDER II. 



Chondropterygii Branchiis Fixis, or Cartilagiiwus Fish 

 7uith fixed gi/is. (From tlie Latin l>ra/ichicr, gills, and fixis, 

 fixed.) — These fish have their gills fixed at the outer edges, with 

 a separate opening through which the water from each gill 

 escapes. They have also small cartilaginous arches suspended 

 in the muscles opposite the gills, which may be called gill-ribs. 



They form two Families. 



The foregoing eight Orders are again subdivided 

 into FamiHes, Genera, and Species, as already 

 stated. 



The following List exhibits in a tabular form 

 the classification above explained, with the addi- 

 tion of the names of the various Families : — 



