CRUSTACEA— OSTRACODA. 357 



hinge; left valve with strong ventral node (''pouch"), surface 

 pitted. (Type of genus.) 



Bryozoan bed (Onondaga) of Falls of Ohio. 



XXXIII. HoLLiNA Ulrich and Bassler. 

 Equivalved, elongate, tapering anteriorly; marginal frill, con- 

 cave on inside, overhanging contact edge and often wanting an- 

 teriorly. A rounded node near hinge line, partly in front of center, 

 a second usually smaller, is lower and behind the center; they may 

 be joined but are generally separate ; other nodes and ridges may 

 occur. Twelve species. Devonic-Carbonic. 



78. H. insolens (Ulrich). (Fig. 1663, /, in.) Devonic. 

 Marginal frill ending posterodorsally in a rounded node, and 



is continued upward from ventral end in curved ridge nearly to 

 main node ; another elongate node below the posterior one, and 

 a curved one in anterior end. (Type of genus.) 

 Bryozoan bed (Onondaga) of Falls of Ohio. 



79. H. antispinosa (Ulrich). (Fig. 1660, 3^, 3;', 3;".) Devonic. 

 Principal nodes connected by rounded ventral swelling; a third 



elongated node in anterior end, with marginal frill extending to it. 

 Bryozoan bed (Onondaga) of Falls of Ohio. 



80. H. armata (Ulrich). (Fig. 1660, ^.) Devonic. 

 An elongate swelling below main node, and ending in blunt 



node ; a more spinose node below the secondary one ; marginal 

 frill indefinite. 



Bryozoan bed (Onondaga) of Falls of Ohio. 



81. H. cavimarginata (Ulrich). (Fig. 1660, w^zv'^x.) Devonic. 

 Differs from preceding in having marginal frill thick on pos- 

 terior half and pitted on interior; swelling below main node end- 

 ing in two nodes. 



Occurs with preceding. 



82. H. spiculosa Ulrich. (Fig. 1660, w.) Devonic. 

 Marginal frill thick, pronounced, extending around two thirds 



of free margin ; a stout spine occurs behind the secondary node, 

 and the surface, hinge line, and anterior margin are marked by 

 scattered spinules. 



Bryozoan bed (Onondaga) of Falls of Ohio. 



