136 ON THE FOSSIL CORALS OF THE 



by the transverse diaphragms ; sometimes in well preserved specimens 

 the septa may be seen extending about half waj to the centre upon 

 the surface of some of the diaphragms, but in general they are con- 

 fined to the outer area. In the more dense colonies the corallites 

 often inosculate, and are sometimes connected by lateral processes, 

 as in species of the sub-genus Mnodophyllum. 



This species is almost identical with D, Gracile, McCoy (op. cit. 

 p. 88,) but differs in the following respect : Z>. 'Jracile has about 

 forty septa, one half of which are very minute or greatly less than the 

 others, but in D. stramineum the septa, about forty in number, are 

 all nearly equal. 



Locality and Formation. — Common in the Corniferous limestone^ 

 lot 6, con. 1, "Wainfleet. There is a specimen in the Cabinet of the 

 Canadian Institute at Toronto from near Simeoe. 



Genus Ctstiphtlltim. — (Lonsdale). 



Generic Characters. — Corallum simple or aggregate, entirely filled 

 with vesicular tissue j radiating septa, rudimentary or obsolete. 



Ctstiphylxum sulcatum. — (Billings) . 



Description. — Short, turbinate, much curved, expanding at the 

 rate of between forty and forty-five degrees from the minute sharp 

 curved point upwards \ cup oblique, the lower margin being on the 

 side of the lesser curvature, moderately deep, and nearly regularly 

 concave, the bottom covered with obscure coarse rounded radiating 

 ridges j a shallow rounded groove or fossette extending from the centre 

 to the higher margin, and in some specimens two others much less 

 distinct, radiating to the sides at right angles to the main groove. 

 Exterior encircled by obscure undulations, and longitudinally striated 

 by the rudimentary radiating septa. The vesicular structure consists 

 of irregular sub-lenticular cells, from half a line to two lines in width ; 

 length of the convex side, from one inch and a half to three inches^ 

 the usual length appears to be about two inches or a little more ; 

 width of cup from one inch to one inch and a half; depth about half 

 an inch. 



This species, when the interior cannot be seen, might be mistaken, 

 upon a superficial examination, for a small curved Cyathophyllum or 

 Zaplirentis. It is about the size land shape of the curved specimens 

 of Petraia cornicula. 



