414 G. HERBERT FOWLER. 



the interest of some of the forms which I am about to describe 

 lies in the fact that they exhibit a certain divergence from 

 both the structural types mentioned above. An account of the 

 following species will be found below. 



Madracis asperula, p. 414. 

 Ampliibelia ramea, p. 416. 

 Step ban ophy Ilia formosissima, 



p. 418. 

 Spheuotrochus rubescens, p. 421. 



Stephanaria planipora, p. 424. 

 Pocillopora nobilis, p. 425. 

 Seriatopora tenuicornis, sp. n., 

 p. 426. 



Madracis asperula (fig. 1). 



For the material for a study of this coral I am indebted to 

 the courtesy of Mr. John Murray, who has placed in my hands 

 the remainder of the spirit collection of Madreporaria obtained 

 during the voyage of H.M.S. " Challenger." 



In systematic position this coral is ranged by Martin Duncan 

 close to the genus Stylophora, of the anatomy of which Dr. von 

 Koch, of Darmstadt, has already published an account (' Jen. 

 Zeitschr./ xi). From this, however, Madracis differs in an 

 important point. 



The corallum, which requires here no systematic descrip- 

 tion, branches in digitate lobes, above the general surface of 

 which the thecse of the polyps project slightly. As in Seria- 

 topora, Stylophora, and other such, it is Imperforate ; the 

 living tissues are confined to the external surface, and do not 

 penetrate into the depth of the colony, the cavity formerly 

 occupied by each polyp being shut off by a succession of 

 " tabulse" as growth proceeds. 



The septa are eight in number, Madracis thus adding 

 another to the several exceptions to Milne-Edwards' law, 

 recently described. With this divergence, however, are not 

 correlated in Madreporaria such marked structural differences 

 as characterise the Monaulese, Edwardsise, &c, which simi- 

 larly diverge from Hexactinian symmetry. The septa are 

 entoccelic only. 



The polyps are in the main of Actinian structure; the 

 body wall clothing the whole colony is composed of the ordi- 



