﻿88 EVOLUTION IN THE PAST 



dants of these fishes never advanced to structure of higher 

 character ; and the gristly skeletoned sturgeon, with his 

 bony armour, and old-fashioned tail, may be regarded as 

 their living representative. 



Flexibly finned ganoids with tails of modern type were 

 now far more numerous than their primitively tailed 

 brethren. 



Prominent among these more accomplished swimmers were 

 some deep-bodied fishes (Dapedius), belonging to a family of 

 late Permian origin (Stylodontidce), and some of spindle shape 

 (Lepidotus), members of a family first known in the Trias 

 (Setnionotidce). But although modernism was evident in their 

 tail-structure, their bony scales were of remarkable thick- 

 ness, and their internal skeletons had undergone but little 

 ossification. 



Other forms were thinner scaled, and well ossified inter- 

 nally (Caturus furcatus, etc.). Some of these were salmon- 

 shaped (Hypsocormus) ; others resembled the bony pike 

 (Aspidorhynchus). The most remarkable of all were sprat- 

 like forms with backbones completely ossified (Leptolepis 

 TELEOSTEANS spYattifoYmis). Ganoids — protected typically by hard and 



enamelled bony scales, and possessing a more or less gristly 

 internal skeleton— had now definitely given rise to a new 

 group of fishes. True bony fishes, in short, were now in the 

 seas (Teleosteans). 

 vegetation Fine forests adorned the land, but, so far as is known, 

 the leafy wealth was much the same in character as that of 

 the Trias. Conifers, cycads, and ferns still held the field ; 

 and in some regions araucarias and allied forms attained 

 grand proportions. Cycads were extraordinarily abundant, 

 and extended over vast territories in all parts of the world. 

 Indeed at no future time were they so widespread, and so 

 varied in species — a startling contrast with their present 

 circumscribed limits, and impoverished condition. " Horse- 

 tails " showed no sign of recovering their lost importance. 

 They certainly stood out here and there like giant forms of 

 old ; but for the most part they were of very humble propor- 

 tions. Their old associates the club-mosses appear to have 

 collapsed to the size of shrubs and bushes. And the pillar- 



