Species of Poly zoa from the Devonian Rocks. 



81 



Genus Carinopora (Nicholson) . 



Polyzoary infundibuliform, calcareous, and reticulated. 

 The external layer of the cyathitbrm frond is composed of 

 regularly undulated flexuous branches ("interstices"), which 

 anastomose with one another, after the manner of a Retepora^ 

 so as to form a series of oval fenestrules. Exteriorly the 

 branches are angulated or carinate, and are smooth and non- 

 celluliferous. Internally each branch gives origin to an 

 enormously developed keel or vertical lamina, which corre- 

 sponds in direction with the branch, and is directed inwards 

 towards the centre of the funnel. The inner surface of the 

 branches thus presents a series of parallel ridges of great 

 height, separated by deep grooves, at the bottom of which, to 

 all appearance, the cells open. The fenestrules also open at the 

 bottom of these grooves. In parts of the frond, however. 



Fie:. 2. 



Illustrations of the structure of Carinopora Hindei, Nich. : a, fragment 

 of the exterior, natural size ; h, portion of the same, enlarged ; c, another 

 portion of the exterior, still further enlarged ; rf, a fragment from which 

 the external non-celluliferous layer has been removed, showing the 

 cells, enlarged ; e, a fragment more deeply decorticated, showing the 

 mouths of the cells, enlarged ; / & (/, transverse sections of the frond in 

 different parts, enlarged ; h, a portion of the internal surface, enlarged ; 

 i, transverse section of a single branch, enlarged. 



these grooves are apparently rendered vesicular by the deve- 

 lopment of a series of delicate calcareous lamina3, which connect 

 together the sides of contiguous ridges. In some cases, also, 

 the inner edges of the ridges are connected together by a con- 

 tinuous calcareous membrane, so that the inner surface of the 

 frond is completely closed. The cells are carried in alternating 

 double rows upon the inner and lateral aspects of each branch, 

 their mouths a|)pearing to be situated at the bottom of the 

 grooves before mentioned and at the base of the great keel 

 which springs from each branch internally. Obviously , how- 



