464 



HISTORICAL GEOLOGY 



Lungfish. 1 — (1) Armored Lungfish. — The most formidable and 

 remarkable fish of the Devonian, as far as appearance and size 

 is concerned, were related to the rare lungfish of to-day, although 

 they probably did not possess lungs. One of the most remarkable 



Fig. 441. — Armored lungfishes : A, Dinichthys, the giant fish of the Devonian, 

 some of which attained a total length of more than ten feet, with head three feet long; 

 B, Coccosteus, a fish of much smaller size. 



of the Devonian lungfish was the Dinichthys (Greek, cleinos, terrible, 

 and ichthus, a fish) (Fig. \\\A) which grew, in one species, to be 25 

 feet long, and resembled an overgrown catfish, in external form. The 

 head, which in one species was six feet broad, and the front of the body 

 were protected by thick bony plates, although the posterior portions 

 seem to have been quite naked unless covered by a leather-like skin, 



Fig. 442. — An unarmored lungfish, Scaumenacia. 



as is perhaps indicated by certain marks upon the exterior of the bony 

 plates. Their powerful jaws were adapted for tearing and cutting, 

 and their shape formerly led to the belief that these fish were fierce, 



1 There is mui b doubl as to the relationship of the armored lungfish, some holding that they 

 should be placed with the higher ostracophores (Bothriolepis, etc., in the group Placodermata), 

 retaining for the rest of the ostracoderms (Cephalaspis) the name Enostracophori. 



