CRETACEOUS ERA. 



145 



Bairdia, cy there, cy thereto, cytheretta, &c., while the larger 

 malacostracans ahound in numerous generic forms, myeria, 



1, Uarsupites ; 2, Goniaster ; 3, Hamipneustes ; 4, Ananchytes ; 5, Galerites. 



pagurus, notopocorystes, &c., all more nearly approaching 

 in aspect and function the crabs and lobsters of existing 

 waters. And now the minute polyzoans or sea-mats weave 

 their delicate tracery of network in a thousand forms (flus- 

 tra, eschara, diastopora, actinopora, idmonea, &c.), spread- 

 ing it over corals, dead shells, and crustaceans, as if their 

 function had been to shroud in beauty the worthless and 

 decaying wreck of the cretaceous sea-shore. The higher 

 mollusca also appear in vast profusion many of the oolitic 

 genera having departed or being on the wane, while other 

 forms peculiar to the chalk begin to make their appearance. 

 The deep-sea brachiopods are represented by species of 

 terebratula, terebratella, and rhynconella ; the true bivalves 

 by inoceramus, lima, ostrea, pecten, astarte, cardiitm, tri- 



