BRYOZOA. 585 



LYROPORA OVALIS Ulrich. 



PL LYin, Fig. 5-5b, and PI. LY, Fig. 8. 



Of this species I have seen only the imperfect example figured. 

 It does nott preserve any of the basal portion of the support, 

 but the sides of the expansion are thickened in the manner 

 usual for the genus. Contrary to the rule the reverse is the con- 

 vex side. Here the branches are rounded and appear to inoscu- 

 late, forming a regular net-work, leaving suboval or circular 

 fenestrulHs. about ten in the length of 1 cm. Branches about 

 sixteen in 1 cm., with a nearly smooth surface; their width, as 

 a rule, is a little less than the transverse diameter of the fenes- 

 t rules. The obverse being buried in the matrix, the arrange- 

 ment of the zooecia and and other features were determined by 

 means of thin sections. These show that the zocecla are larger 

 than usual (especially wider) there being about twenty in five 

 mm. The prevailing arrangement is in two ranges, but three 

 rows occur for a distance of 2 or 3 mm. below the bifurcations, 

 i own by vertical section (PI LV, fig. 8,) the inferior hemi- 

 septum is situated higher up on the anterior wall than in other 

 species. 



The two ranges of zooecia ally this species to L. divergens 

 Ulr.. and L. c/uincuncialis Hall, but the net-work is considerably 

 larger than in those species. Both L. subquadrans Hall, and 

 L. ranosculuw L'lr.. have from three to five rows of apertures. 



Position and locality: Chester group, Grayson Springs, Ken- 

 tucky. 



POLYPORA McCoy, 1844. 



(Synop. Carb. Foss. Ireland, p. 206. 

 (For generic diagnosis see page 396..) 



In my estimate of this genus I regard such forms as P. shu- 

 niardi and P. rai-soviensis. as representing its most typical 

 phase. McCoy's P. dendroides is one of a series (to which P. 

 cestriensis, P. tuberculata. and P. gracilis also belong), that 

 approaches Thamniscus too closely to make it a desirable type. 

 I regard it as farther removed from P. shumardi than are the 

 numerous two and three ranged forms/ 

 73 



