io6 EVOLUTION IN THE PAST 



the voracious dorabs of our own time (Chirocentrus). There 

 were also many spiny-finned fishes. These evidently had. 

 an excessive supply of bony substance, and the surplus 

 was finding its way along the fins. The most numerous of 

 the company were closely related to the Beryx of our own 

 time {Hoplopteryx). Others seem to have developed more or 

 less into horse-mackerel (Aipicthys), sea-perches (Prolates), 

 and sea-bream (Pagellus). 



Fishes with the pelvic fins brought forward, and greatly^ 

 enlarged as if for flying purposes, were also to be seen 

 (Chirothrix). Fishes eel-shaped — and therefore degenerate 

 — were numerous (Echidnocephalus, Dercetis, etc.) ; and 

 true eels were in existence (Urenchelys). Here also were 

 fishes of the family to which tarpons belong (Elopidce) ; and. 

 many other forms were abroad, belonging to families which 

 exist to-day (Albulidce, HalosauridcB, Scopelidce, etc.). 



In addition to these, there were various bony fishes, 

 divers in form, and of uncertain affinities (Ctenothnssa, etc.). 

 Indeed in late Cretaceous times there was a decided boom, 

 in the fish world, resulting from the new anatomy. An 

 analogous outburst of activity may be witnessed on a small 

 scale in human affairs, consequent on some great discovery or 

 invention. 



Notice must now be taken of the lower classes of the 

 marine population. 

 CRUSTACEANS Many crustaceans in Jurassic times had become recognis- 

 able as shrimps, prawns, and lobsters. In the Cretaceous. 

 Period all these differentiated creatures became more dis- 

 tinctly defined, and of greater variety. New forms of prawns 

 (Hoplophorus, etc.) and various small lobsters {Enoplodytia, 

 Clytia Leachii, etc.) were now in being. Among the latter 

 some essentially resembled the Norway lobster of our own 

 time (Nephrops) : other allied forms were probably in- 

 distinguishable from the modern Crawfish (Palinurus). There 

 were also numbers of lobsters that had taken to embedding; 

 themselves in mud (Callianassa). 



But it was in crab-life that the greatest developments 

 were in progress. Crabs, although foreshadowed in far-back, 

 times, cannot be said to have expressed themselves un- 



