THE CARBONIFEROUS PERIOD. 



183 



netted wings attaining an expanse of fully seven inches, and 

 therefore much exceeding any existing Ephemerid in point 

 of size. 



The lower groups of the Mollusca are abundantly represented 

 in the marine strata of the Carboniferous series by Polyzoans 



Fig. 126. Carboniferous Polyzoa. a, Fragment of Polyfiora dendroides, of the natural 

 size, Ireland ; a' Small portion of the same, enlarged to show the cells ; b, Glaucotwnie 

 pnlcherrima, a fragment, of the natural size, Ireland; f. Portion of the same, enlarged; 

 c, The central screw-like axis of Archimedes IVortheni, of the natural size Carboniferous, 

 America ; c 1 , Portion of the exterior of the frond of the same, enlarged ; c". Portion of 

 the interior of the frond of the same showing the mouths of the cells, enlarged. (After 

 M 'Coy and Hall.) 



and Brachiopods. Amongst the former, although a variety of 

 other types are known, the majority still belong to the old 

 group of the " Lace-corals " (Fenestellidcz), some of the charac- 

 teristic forms of which are here figured (fig. 126). The graceful 



