CELLEPORA COSTAZII. M -> 



is orbicular, and there is a well -marked sinus below ; as 

 growth advances, however, it is more or less concealed by 

 the elevation of the peristome, which usually forms a thin 

 and shallow rim or border round the front. In the very 

 curious and interesting variety (tubulosa) , the peristome is 

 prolonged into a suberect tubular shaft, within which the 

 orifice is deeply sunk. In this form the tubular extension 

 of the peristome rises above the ovicell, which is situated 

 behind it. In old specimens, in which the ocecia are 

 freely developed, the species takes on a different and 

 very picturesque appearance. In some cases the inclosed 

 area on the front of the orecium is perforated with large 

 punctures ; in others it is simply furrowed. This is a 

 trifling difference, the furrowed condition being probably 

 due to the confluence of the pores. 



The cells are smooth and generally dull and opaque ; 

 but in some forms they are of a more delicate texture and 

 almost hyaline. 



Though the list of localities is comparatively small, C. 

 Costazii is, I believe, a common species. It occurs abun- 

 dantly on the stems of various Hydroid zoophytes, over 

 which it spreads in minute colonies. 



\Thefollowing genus should have been placed amongst 

 the Porinidse, page 226.] 



Genus CELLEPORELLA, Gray. 



Der. Dim. of Ctllepora, a genus of Polyzoa. 



GENERIC CHARACTER. ZO<ECIA suberect, the anterior 

 extremity tubular and free, with a terminal circular orifice. 

 No special pores. ZOARIUM (in the British species') in- 

 crusting. 



