imperfectly-known Species of Stromatoporoids. 15 



Stromatoporella (?) tuherciclata, Nich. 

 (PL III. fig-s. 9-11.) 



Sfromatopora tuberculata, Nicliolson, Ann. & Mag. Nat. Hist. ser. 4, 

 vol. xii. p. 92, pi. iv. fio-s. 2, 2 a (1873) ; ibid. vol. xiii. .p. 8, fig. 1 

 (1874) ; Report on the Palaeont. of Ontario, p. 14 (1374). 



Coenosteum of large size, laminar, the underside covered 

 with a wrinkled epitheca. Upper surface often irregularly 

 undulated, without " raaraelons," but covered with prominent, 

 close-set, blunt tubercles, the summits of which appear some- 

 times, perhaps from breakage or weathering, to be perforated 

 (PI. III. fig. 9). As regards internal structure, the skeleton 

 is composed of nearly horizontal or gently flexuous concentric 

 laminte, of which from three to four occupy the space of 1 

 niillim. The laminge are not crumpled, but exhibit slight 

 upward and downward foldings, being bent upwards at the 

 points where radial pillars are developed. (PI. III. fig. 11). 

 The radial pillars are placed at distances of from f to 1 raillim. 

 apart, and are extremely stout ; they are apparently hollow, 

 sometimes with a central axis, and they seem as if formed by 

 successive cone-shaped upward prolongations of the concentric 

 laminse. Vertical sections show the interlaminar spaces to be 

 traversed, in addition to the proper radial pillars, by numerous 

 curved or straight calcareous partitions, which are very deli- 

 cate, and may be spoken of as " interlaminar septa." 



Tangential sections (PI. III. fig. 10) exhibit the very large 

 oval or ring-like cut ends of the radial pillars, which are con- 

 nected with one another by numerous delicate curved lines, 

 these representing the cut edges of the " interlaminar septa." 



The skeleton-fibre itself is penetrated by innumerable 

 minute tubuli or is finely porous. Astrorhiz^, if present at 

 all, seem to be only incompletely developed. 



Ohs. This very remarkable species was originally referred 

 by me to the genus Stromafopora, Goldf., which was at that 

 time believed to comprise the forms which I now include in 

 the genus Actinostroma, In its general structure it certainly 

 most nearly resembles Actinostroma^ and it has even points 

 of likeness to Lahechia. It clearly cannot be referred, how- 

 ever, to either of these genera, and it may be an open question 

 whether it should not be regarded as the type of a \\q\y genus. 

 In the meanwhile I have referred it to the genus Stromato- 

 jporella^ Nich., with which it agrees in the porous or tubulated 

 condition of the skeleton-fibre. It also resembles certain of 

 the species of Stromatoporella (e. g. S. arachnoidea, Nich.) 

 in the great development of " interlaminar septa." In any 

 case, I know of no other type of the Stromatoporoids with 



