PISCES, TRUE FISH 



443 



tends into the dorsal lobe as has already been seen in the dogfish. 

 Still another type of tail is the liomocercal, which is internally un- 

 balanced but externally symmetrical. The original notochord turns 



Fig-. 240. — Spiny boxflsh, Chilomycterus schoepfli, from Gulf of Mexico and Atlantic 



Ocean. 



Fig. 241. — Diagram showing some peculiar bony fish. A, common eel ; -B, sea 

 horse; C, flying fish. (From Krecker, General Zoology, published by Henry Holt 

 & Company, after Jordan.) 



into the dorsal lobe, but the lobes stroke the water with about equal 

 surface and force. It forces the fish through the water in a hori- 

 zontal plane and is correlated with a terminal mouth. 



