107 



Ptychophtllum Canadense. TN. sp.) 



Description. — Corallum large, obtusely pedicillated, the base turbinated 

 for a height of one or two inches, then abruptly expandmg so as to form a 

 wide circular horizontal disc, from four to eight inches in diameter. Ra- 

 diating septa from eighty to one hundred. These are closely crowded 

 together at the centre of the fossil, but become more widely separated as 

 they recede towards the margin. At 2i inches from the centre in one 

 specimen they are 2i lines apart ; at four inches in another larger indivi- 

 dual they are 3| lines distant from each other. Judging from the cast of 

 a cup of this species, the septa must be elevated a little above the surface 

 of the disc ; the intervening spaces being slightly concave. In several 

 specimens the base, instead of sho-\ving an acute point of attachment, is 

 excavated into a cup-like cavity, | of an inch in depth. The central por- 

 tion of the upper side seems to be only slightly elevated above the general 

 surface of the widely expanded disc. The under side of a large specimen 

 which is somewhat worn is covered with numerous concentric flexuous 

 raised lines, three or four in the width of one line. In another it is smooth 

 as if protected by a dense epitheca. 



Locality and Formation. — South-west point, Anticosti ; in division 4, 

 Middle Silurian. Associated with Pentamerus ohlongus. 



Collector. — J. Richardson. 



Cyathophyllum Pennanti. (N. sp.) 



Description. — Forming large colonies from 2 inches to 2 feet in diame- 

 ter, consisting of long, slender, often straight corallites, 4 or 5 lines in di- 

 ameter. The young appear to bud from the side of the adult, and also in 

 some instances from the cup. The surface of the corallites is in general 

 somewhat smooth, but in colonies which have had a disturbed growth it is 

 more irregular, being annulated with obscure accretion ridges, and present- 

 ing occasional swellings or enlargements of the diameter. In some there 

 are a few lateral projections which connect the contiguous coraUites, as in 

 the genus Eridophyllum. In the transverse section there are seen about 

 60 radiating septa, one half of which seem to reach very nearly to the 

 centre. In the longitudinal section, the transverse diaphragms in the 

 central half form, with the radiating septa, a tissue of square or oblong 

 cells. In some places where the transverse diaphragms alone are visible, 

 the cells are greatly elongated horizontally. The outer vesicular area is 

 filled with oval or irregularly reniform cells, with curved sides, and some 

 acute angles, from 4 to 8 cells in the width of one line. 



