96 THE FAR PAST. 



with huge prehensile claws, they present the zoologist 

 with an entirely distinct family (Eurypteridae), if not with 

 the elements of a new and separate legion. Some of 

 the species are of great size three, four, and six feet in 

 length and seem to have been the scavengers of their 

 period, living on the lower forms and garbage of the sea- 

 shore ; and so it happens that wherever they are found 

 entire fishes are rare, though their heads, fin-spines, and 

 other unmanageable portions occur in abundance. Another 

 curious feature in connection with these Crustacea, and oc- 

 curring in the same beds, is an immense number of dark- 

 coloured patches of spawn-like organisms, which are now 

 pretty generally regarded as the egg-packets of eurypterus and 

 pterygotus. Compressed and flattened, the ova appear less 



Parka Decipiens Supposed Spawn or F.gg-packets of Crustacea. 



or more in concentric arrangement, and every appearance 

 favours the idea of their crustacean origin, unless, perhaps, 

 their great abundance, which has suggested to some the 

 possibility of their being the berries or carpels of some un- 

 known plant. The egg-packet theory is now the most 

 prevalent, and, admitting its truth, the widespread abun- 

 dance of these remains increases beyond expression our 

 notions of the exuberance of crustacean life within certain 

 areas of the old red sandstone. 



The Fishes of the period are also peculiar, inasmuch as 

 many of them are encased in bony plates, or covered with 



