202 ANATOMY AND AFFINITIES OF THE GENUS PTERYGOTUS 
papyraceous film, is not inconsistent with great solidity in the recent 
condition, is shown by the existing Lziul/us, whose leathery integu- 
ment is thick and hard enough to give firm attachment to very large 
and powerful muscles, and yet contains so little calcareous matter, 
that when dried and subjected to such pressure and decomposing 
influences as have operated upon the Péerygodz, it would probably be 
hardly more bulky. 
It is not without interest to find that the skeleton was as perish- 
able in the Crustacea as in the Vertebrata of the period in which the 
Prerygoti flourished. 
Note, p. 193.—So long ago as 1840, Milne Edwards indicated the relations of Zuryplerus 
with the Cofepoda in the following words :—‘‘ The fossil Crzstacea of which M. Dekay 
has formed the genus £uvypterus appear to have much analogy with Ponca (Pontella) and 
Cyclops, and also seem in some respects to forma link between these animals and the /sopoda.” 
—Hist. Nat. des Crustac¢s, t. ili, p. 422. 
