132 PALAEONTOLOGY OP ONTAEIO. 



surface, where decorticated, exhibits reticulating lines which corres- 

 pond with the bases or proximal ends of the cells. The internal 

 surface of the intermediate layer carries the cells, which are flask- 

 shaped, and are arranged in double rows, forming flexixous lines 

 enclosing oval interspaces, just as in Retepora. The oval interspaces, 

 however, instead of constituting so many " fenestrules," are the bases 

 of so many pillars which proceed perpendicularly inwards, across a 

 central space, to join with an internal calcareou.s membrane which 

 forms the innermost lining of the funnel-shaped frond. It follows 

 from the above that the mouths of the cells in Cryptopora neither 

 open on the exterior of the frond, as in Fenestella and Hemitrypa, 

 nor open on the interior of the polyzoary, as is the case in the infun- 

 dibuliform species of Retepora. On the contrary, we have in this 

 remarkable genus the unique arrangement that both the internal and 

 external aspects of the funnel-shaped frond are to all appearance 

 closed by a continuous calcareous membrane. The cells, therefore, 

 ai-e not placed upon either of the free surfaces of the polyzoary, but 

 open into a central space between these two membranes. The limit- 

 ing membranes of this space are kept apart by a system of pillars 

 which are directed at right angles to the plane of growth of the 

 frond, and correspond in position with the fenestrules of a Retepora. 

 The water must have been admitted to this central space, and thus 

 to the cells, by openings in the free edge of the infundibuliform 

 polyzoary. The only species of this genus known to me occurs in 

 the Gorniferous Limestone, and I have named it Cryptopora mirabilis. 

 2. Carikopora, gen. nov. — ^Polyzoary infundibuliform, calcareous, 

 and reticulated. The external layer of the cyathiform frond is com- 

 posed of regularly undulated flexuous branches, which anastomose 

 with one another after the manner of a Retepora, so as to form a 

 series of oval fenestrules. Externally, the branches are angulated or 

 sub-carinate, and are smooth and non-celluliferous. Internally, each 

 branch gives origin to an enormously developed keel or verticsil 

 lamina, which corresponds in direction with the branch, and which is 

 directed inwards towards the centre of the funnel. The inner face of 

 the frond thus presents a series of narrow, elevated, parallel ridges, 

 separated by deep grooves, at the bottom of which both the cells and 

 the fenestrules open. In parts of the frond, however, these grooves 

 appear to be rendered vesicular by means of a series of delicate calca- 

 reous laminse, which connect together the opposing sides of contiguous 



