PHYLUM CHORD ATA 



395 



Flounders, Turbots, etc.). The body (Fig. 221) is very 

 deep and strongly compressed ; the fish habitually rests on 

 the bottom, in some species on the right, in others on the 

 left side. The under side is usually pure white, the upper 

 dark. The eyes are both on the upper side, and the skull 

 is distorted so as to adapt the orbits to this change of 

 position. 



In many Teleostei, such as the Eels, the skin is devoid 



le. 



FIG. 221. Pleuronectes cynoglOSSUS (Craig-fluke), from the right side. d.j. 

 dorsal fin ; /. e. left eye ; pct.f. pectoral fin ; pv.f. pelvic fin ; r. c. right eye ; 

 v.f. ventral fin. (After Cuvier.) 



of hard parts ; but in most cases there is an exoskeleton 

 developed in the derm. In the majority this takes the form 

 of scales rounded plates of bone embedded in pouches of 

 the derm, and overlapping one another from before back- 

 wards. When the free border of the scales presents an 

 even curve they are called cycloid scales ; when the free 

 edge is produced into small spines they are distinguished 

 as ctenoid scales (Fig. 222). In exceptional cases the scales 



