84 



llEl'OilT — 1880. 



spreading irregularly, forming large patches, at other times mere minnte 

 specs ; pores generally oval, separated from each other by smaller open- 

 ings. I cannot call them ' interstitial or csenenchymal tnbuli ' — for that 

 would convey a false impression, for pores and cells are netted together. 

 The number of small openings surrounding a cell varies ; sometimes there 

 are as many as fifteen, in other places not more than five or seven. About 

 twelve clUs with their interjacent pores occupy the space of a line and 

 half across the cells, fi om nine to ten in the same space in their length. 

 The polyzoary is separated from the foreign objects to which it is attached 

 bj a very tliin lamina formed by the bases of the cells. There is no evi- 

 FlG. 1. ' f iG. 2. 



Fig. 3. 



Archseopora nexilis, De Koninck, Capelrig E. Kilbride, Scotland. 



Fig. 1. Showing the different sizes of the cells and interjacent pores. 



2. More highly magnified, show vacant ' areolae.' 



3. Transparent, showing sections of interjacent pores ; the long arm-like processes put in 



by reflected light. 

 (Drawn with Camera lucida by G. E. Vine, jiinr., June 1880.) 



dence of tabulae in thin sections, but the interjacent pores do not reach 

 quite to the bases of the cells. I have never seen a specimen, on which 

 a fresh colony is found spreading over an older one, but sometimes a 

 colony of Stenopora is found upon the polyzoary of Archceopora. In a 

 thin transparent section of a small fragment of another specimen, adhe- 

 rent to a portion of shell, a most peculiar structure is revealed — a draw- 

 ing of which is given, which for a long time puzzled me — because the 



