THE TRUE FISHES. 165 
FIG, 202.—Devil-fish (Cephalopterus diabolus). 
Order II. Holocephali.—The Chimera (Fig. 203) is 
a northern representative of this group, while the curious 
Callorhynchus is found in Antarctic regions. The gill- 
openings are protected by a membranous covering, sug- 
gesting the gill-covers of bony fishes. The teeth are curi- 
ously arranged, there being four in the upper and only two 
Fic. 203.—The Chimera. 
in the lower jaw. The air-bladder is absent. The male 
Chimera has.a curious, comb-like, cartilaginous appendage 
armed with hooklets on the top of the head, that is either 
erect or hidden in a hook-armed groove. 
