162 Prof. H. A. Nicholson — Neiv Devonian Fossils. 



than the branches, and placed at intervals of about half a line apart. 

 Fenestrules regularly oval, half a line in length, and about a quarter 

 of a line in width, four or five in the space of three lines, alternate 

 or sub-alternate in contiguous rows. The upper or inner surface of 

 the branches carries the cells, three rows of which occur on every 

 branch, and sometimes four opposite the origin of the dissepiments. 

 The cells are flask-shaped, sometimes slightly unequal in size, their 

 mouths round, those of the central row alternating with those of the 

 lateral rows. From six to eight pores in the space of a line, or three 

 to four in the length of each fenestrule. The reverse face of the 

 polyzoary is smooth or obscurely striated. 



The species to which this is most nearly allied is P. Halliana, 

 Prout, which occurs in the St. Louis Group of Illinois, and which 

 I have likewise detected in the Corniferous formation of Ontario. 

 P. pulchella is, however, readily distinguished by the greater develop- 

 ment of the . dissepiments, the greater proportionate and absolute 

 width of the fenestrules, and the possession of three (instead of four) 

 rows of cells on each branch. 



Locality and Formation. — Common in the Corniferous Limestone 

 of Port Colborne, and Lot 6, Con. 1, Wainfleet. 



PoLYPORA TENELLA, Nicholson. PL IX. Pig. 19, h. 



Polyzoary small, forming a flattened expansion ; branches radiat- 

 ing from the base, and increasing by bifurcation at intervals of 

 about two lines. Branches narrow, about eight in the space of three 

 lines, their width being about a quarter of a line. Fenestrules oval, 

 about eight or nine in a space of three lines measured longitudinally, 

 and ten in the same space measured diagonally ; the length of each 

 about half a line, the width a third less. Dissepiments very short 

 and narrow, without pores. Cells arranged in three alternating 

 rows on the branches, ojjening by minute rounded apertures, two 

 or three of which occupy the length of a fenestrule. Keverse un- 

 known. 



This pretty little species is nearly allied to P. pulcTiella and P. 

 Halliana ; but is distinguished by its much more delicate propor- 

 tions, its narrower and more closely-set branches, and its smaller 

 fenestrules. 



Locality and Formation. — Bare in the Corniferous Limestone, 

 Lot 6, Con. 1, Wainfleet. 



POLYPOBA TUBEKOULATA, NicholsOn. PI. IX. Fig. 20. 



Polyzoary small, forming a flattened expansion, which springs 

 from a strong foot-stalk. Branches radiating from the base, and 

 increasing by bifurcation at intervals of about a line and a half; 

 from a third to half a line in breadth, rounded and destitute of 

 carinas. Dissepiments very short, widest at their junction with 

 the branches. Fenestrules somewhat irregular in shape, usually 

 a very long oval, always longer by from one-half to two-thirds than 

 wide ; having an average width of a third of a line to half a line, by 

 a length of one line or a little less. Two fenestrules in the space of 

 two Imes measured longitudinally, four in the same space measured 



