BRYOZOA. 601 



POLYPORA XODOCARIXATA Ulrich. 

 PI. LXI, fig. 9-fla. 



Zoariuru infundibuliform, large, thrown into strong folds to- 

 ward the tipper margin, poriferous on the inner side. Branches 

 moderately strong, rigid, averaging ten to 1 cm., 0.5 or 0.6 

 mm. wide at a point immediately above a bifurcation; the width 

 gradually increases to 0.7 mm., which prevails till a short dis- 

 below the next bifurcation when another 0.1 mm. is added 

 The bifurcations being widely separated,' the increase is very 

 gradual. Dissepiments short, depressed, rounded, 0.3 or 0.4 

 mm. wide. Fenestrules oval or subquadrangular, about 0.7 by 

 '0.3 mm., and 8.5 or 9 in 1 cm. Zooecia in four regular alter- 

 nating ranges, excepting for a short distance after bifurcation 

 where three is the prevailing number-, and occasionally just be- 

 fore bifurcation where a fifth row may be developed. Apertures 

 circular, without a peristome, about their diameter apart, nine- 

 teen in 5 mm. The ranges of apertures are separated by three 

 rows of tubercles, of which the central row is much the most 

 conspicuous, giving the branch the nodo-carinate appearance 

 that has suggested the name. Frequently, however, the tubercles 

 occupy the longitudinal spaces between the cell apertures when 

 that appearance is less marked. On the reverse the branches 

 are narrowly rounded and appear very thin, the fenestrules are 

 larger, averaging 0. 8. by 0.7 mm., nearly square! or slightly 

 hexagonal. The surface of the branches is smooth over the 

 lower half of the zoarium, and finely striate toward the upper 

 margin. 



The subcarinate branches, with their four ranges of apertures 

 bring to mind F"enextr<ilm sxnc-ti-ludovici Prout. This character, 

 and the nearly square form of the feuestrules on the reverse, 

 distinguish the species from all Carboniferous Polyporse known 

 to me. 



Position and locality: Upper Coal Measures; Crooked Creek, 

 near Ceutralia. 111.; also in Macoupin Co. 



75 



