HAPLOCHITONIDiE, 651 



have been found occasionally on the North British, and, more 

 frequently, on the Norwegian coast. The other species are 

 from the Mediterranean. Attaining to a length of 18 inches. 



Sixteenth Family — PEECOPSiDiE. 



Body covered with ctenoid scales ; head naked. Margin of 

 the upper jaw formed hy the intermaxillaries only ; opercular 

 apparatus complete. Barbels none. Gill - openings wide. 

 Adipose fin present. 



One genus and species only (Percopsis guttatus) ; interest- 

 ing as having the general characters of Salmonoids, but the 

 mouth and scales of a Percoid. Freshwaters of the northern 

 United States. 



Seventeenth Family — Haplochitonid^. 



Body naked or scaly (cycloid). Margin of the upper jaw 

 formed hy the intermaxillary; opercular apparatus complete. 

 Barbels ttene. Gill - opening wide ; pseudohranchice. Air- 

 bladder simple. Adipose fin present. Ovaries laminated ; the 

 eggs fall into the cavity of the abdomen, there being no oviduct. 

 Pyloric appendages none. 



Freshwater-fishes which represent the Salmonoids in the 



Fig. 296. — Prototroctes oxyrhynolius, New Zealand. 



southern hemisphere. Two genera only are known. Eap- 

 lochiton (Fig. 104, p. 250) abundant in lakes and the streams 



