146 NORTH AMERICAN INDEX FOSSILS. 



94. U. acaulis Hall. Devonic. 

 Scalae very slender and closely disposed ; summit of carina very 



prominent, sometimes noded. Length and width of fenestrules on 

 celluliferous face as 3 to 1 ; on non-celluliferous, as 2 to 1. 

 Hamilton of Falls of the Ohio. 



LIV. Loculipora Hall. 

 Funnel-shaped, dissepiments non-poriferous, reduced to a mini- 

 mum, carinated like the branches ; the carinas coalesce and expand 

 at the summits, their width usually equalling that of branches and 

 dissepiments. Sil.-Dev. 



95. L. perforata (Hall). (Fig. 203.) Devonic. 

 Frond regularly reticulated, the fenestrules oval in a depressed 



hexagonal surface, and each surrounded by nine or ten apertures. 



Fig. 203. Loculipora perforata, a, fragment showing manner of growth; b, non- 

 celluliferous face, showing angular slightly carinated branches and dissepiments, X 4 \ 

 c y celluliferous face, X 4- (After Hall.) 



The expansion of the carina may make this face appear like the 

 non-poriferous face. 



Hamilton of New York. 



LV. Hemitrypa Phillips. 

 Differs from Fenestella in a reticulated superstructure, whose 

 meshes correspond in position and numbers^ to the zocecial aper- 

 tures, and rest on pillars which rise at regular intervals from the 

 moderate median keel of the branches. Sil.-Carb. 



96. H. proutana Ulrich. (Fig. 201,/, g.) Mississippian. 



Superficial network of longitudinal bars, united by short transverse 



bars, the former strong over the branches and weaker over the 



interspaces of the underlying frond, the latter alternating in posi- 



