OUTLINES OF ICHTHYOLOGY. 175 



ORDER II. 



The MALACOPTERYGII ABDOMINALES, or Abdominal Soft- 

 finned Fish. (From the Latin abdomen, the belly.) 



So called from the ventral fins being attached to the abdo- 

 men, behind the pectorals, without being jointed on to the 

 shoulder-bones. 



It includes five Families, in which are the greater number of 

 our fresh-water fish. 



ORDER III. 



MALACOPTERYGII SUB-BRACHIATA, or Soft-finned Fish with 

 lower arms. (From Latin sub, under, and brachium, an arm.) 

 Named from their having the ventral fins under the pectorals, 

 thus giving the idea of lower arms. 



In this Order, which consists of three Families, the pelvis is 

 suspended to the shoulder-bones. 



ORDER IV. 



MALACOPTERYGII APODES, or Soft-finned Fish without feet. 

 (From Gr. a, a privative, and pous, a foot.) Have no ventral 

 fins, which, being supposed to represent feet, have thus by their 

 absence given the designation of " Footless." 



Has only a single Family. 



ORDER V. 



LOPHOBRANCHII, Fish ivith their gills in tufts. (From Gr. 

 lophos, a tuft, and branchia, gills.) This arrangement of the gills 

 is peculiar to this Order, which, moreover, have the gill-covers 

 entirely closed behind, with the exception of a single small hole. 



Only one Family. 



ORDER VI. 



PLECTOGNATHI, or Fish with soldered jaws. (From Greek 

 plekein, to bind, and gnathos, a jaw.) This Order has no true 

 ventral fins. Many of its characteristics resemble those of the 

 cartilaginous fish. The chief peculiarity is the maxillary bone 

 being soldered to the side of the inter-maxillary, which consti- 



