1883.] 



MADREPORARIAN GENUS PHYMASTR^A. 



409 



V. Description of a new Species. 



PhYMASTR^A IRREGtJLARIS, Sp. nOV, 



The corallum has a small adherent base and a large irregularly 

 hemispherical shape, the surface being gibbose here and there. The 



Fig. 1. 



Phymastreea irregularis (coraUuiii fiom above). 



Fig. 2. 



Thymastrea irregularis (side view of a corallite). 



corallites are numerous, are small at the base, widen rapidly with 

 height, and are very irregular in their outlines and dimensions"; each 

 is separated from its neighbours even at the calice by a narrow space 

 which is crossed by slender junction-processes. The calices vary in 

 size and shape and are rather deep ; they are angular in outline 



