168 



on a plane with the branches, and slighth' expanding- at 

 their jnnction, with a sHght carina similar to and uniting 

 with that of the branches: elongate to broadly oval fenes- 

 trnles; celhiliferons face; rounded charactei' of bi'anches 



it 



^ ,M. M^ K^ Ji 







yra -.rpn .--j- « - « 



m '?1 'Is ;? # 



anUH tTcE ;-5«i - ? cy 





Fig 51A. Polt/pora miiltiple.r. Portion of a frond natural size: enlartrement of the non- 

 celluliferous face, showing angular branches connected by slender dissepiments, x 6; en- 

 largement of celluliferous face, showing form and disposition of cell apertures, and the 

 stria:^ or ridges l)etween the i-anges of apertures, x 6; transverse sections of different 

 fronds, showing varialion, x 6 ifrom Hall ). 



and dissepiments, the latter slender and much depressed, 

 obscure, and sometimes obsolete; narrow fenestrules, adja- 

 cent branches fi-efpiently almost or quite in contact : cell aper- 

 tures in two to four ranges, circular or oval, closely arranged; 

 smooth interspaces; strong elevated peristomes. 



P^ound in the Hamilton group at Alden, Erie Co. (Hall), 

 and at Eighteen Mile Creek. (Coll. Am. Mus. Nat. Hist., New 

 York.) 



