136 EVOLUTION IN THE PAST 



time are closely allied (Carcharias). And eagle-rays, fore- 

 shadowed in the last Period, were now represented by some 

 gigantic specimens (Myliobatis). Electric rays were also in 

 evidence {Torpedo). These, so far as is known, were the first 

 creatures equipped with electrical organs for the battle of 

 life. 

 GANOIDS Flexibly finned ganoids, although greatly reduced at the 

 close of the Cretaceous Period, were in some force in the 

 Eocene. Deep-bodied pycnodonts, for instance, with power- 

 ful teeth still held their own. They apparently differed in 

 no respect from their Jurassic forefathers ; and they remained, 

 moreover, practically unchanged until the close of the Period. 

 In common with other part-modernised forms — suggestive 

 of old bottles carrying a modicum of new wine — they 

 then became extinct. With better outlook were the descen- 

 dants of the sturgeon-hke fishes. Various forms of these 

 seem to have differed Httle, if at all, from species of sturgeon 

 now in existence. Long-nosed garpike were also abroad 

 (Lepidosteus). These ganoids seem to have commenced their 

 career in the Eocene : and they are represented to-day by 

 some voracious forms in North American rivers. 

 TELEOSTEANS Ganoid glory, however, had now quite passed away, owing 

 to the rapid oncoming of bony fishes. Fishes of this Order 

 (overwhelmingly predominant at the present time) were 

 already in a wonderful condition of development in Eocene 

 seas. To enumerate the various new forms would be to make 

 a Ust of some length, and not of general interest. Suffice it 

 to say that all the Orders and Sub-orders into Avhich existing 

 bony fishes are generally divided were more or less repre- 

 sented. The approximation was even closer than this, for 

 many existing families of the Sub-orders were represented, 

 and even existing genera of some families. Remains, for 

 instance, have been found of present-day genera of herrings 

 and wrasses. 



Countless genera, and many families of Eocene fishes 

 were destined to disappear in course of time ; but, in the 

 light of present knowledge, it can be said that no fishes were 

 henceforth to appear with any important modifications of 

 the skeleton. 



