324 Dr. S. J. Hickson. On certain [Apr. 15, 



Fig. 1. 



Small portion of the skeleton ( x 2) as it appears when dry, showing the longitu- 

 dinal grooves which correspond with the mesenteries (gg), the connecting tubes 

 (tt), and a young polype springing from a connecting tube (p). 



Histologically it does not seem to differ in any important particular 

 from Tnbipora, but I hope in a later and fuller paper to be able to 

 give the results of a further and better investigation. 



The importance and interest of this genus is two- fold. In the first 

 place the structure of the stolon, the mode of connexion of the polype 

 tubes, and the fact that its skeleton is imperforate, show that it is 

 closely allied to the extinct genus Syringopora, which it resembles in 

 all these particulars. Notwithstanding the mass of evidence which 



