174 TELEOSTOMES 
Similarity in eel-like form, e.g. as of Murena, is not in 
itself indicative of direct kinship. (Afodes.) 
The Perch (Fig. 181) has long been taken as a repre- 
sentative Teleost. Perfect in its “lines,” its compact, 
wedge-like shape cleaves the water by vigorous thrusts of __ 
a strong broad caudal; its fins are stout, supported by 
spinous rays ; its dermal armouring light, smooth, and flex- 
ible; its colour is brilliant under its transparent scales, 
So adapted is it to its environment that its organ of static 
equilibrium, the air-bladder, has lost its valvular connec- 
tion with the gullet. Of existing fishes about one-half are 
essentially percoid. (Acanthopterygit.) 
Fig. 182. — The sone, Gadus morrhua, L. X%. (After GOODE in U. S. 
F.C.) North Atlantic. 
The Cod (Fig. 182) is scarcely less important as a repre- 
sentative Teleost. Its structural differences may perhaps 
represent the result of a competition less active than that 
of the perch in the struggle for survival. Heavy in body, 
its sluggish form has become blunted and rounded; its 
fins are depressed, their rays soft and yielding; its scales — 
are reduced in size, colours less vivid; its swim-bladder 
loses its connection with the gullet. As many, perhaps, 
as one quarter of the existing genera of fishes may be 
assigned to this type. (Anacanthini.) 
The Flounder (Fig. 183) should be mentioned as a singu- 
