M 1 M r, i: \ \ IPORA CURVIROSTR1S. 153 



his description and figure, seems to be a distinct form. 

 He represents a large, much elongated avicularium in the 

 spaces between the cells ; but M. discreta is destitute of 

 avicularia. In other respects the two appear to differ. 



In the present species the cells are very irregularly 

 grouped, and vary considerably in size, and the colony has 

 a somewhat confused and disjointed appearance. The 

 entire margin is divided into distinct lobes, ranged closely 

 together, which may be traced down the exterior wall of 

 the cell ; and each of them bears a spine. They number 

 about twenty or upwards. The spines, with the exception 

 of one or two near the top, are very delicate and bend 

 inwards. The ooecium is small and rounded, and mi- 

 nutely granular. 



From M. lineata this species is distinguished by the 

 characters just enumerated, to which the former, I be- 

 lieve, makes no approach in any stage of its develop- 

 ment. 



MEMBRANIPORA CURVIROSTRIS, Hincks. 

 Plate XX. figs. 5, 6. 



MEUBRA.XIPORA CURVIHOSTRIS, Hincks, Devon & Cornw. Cat, Ann. N. H. 

 scr. 3, ii. 29, pi. vii. fig. 4 (p. 39, sep.). 



Zooecia elongate-oval, margin granular and somewhat 

 thickened, the inner edge minutely serrulate ; a short 

 stout spine on each side near the top, which projects in 

 front of the ovicell, and at the bottom a single sub- 

 conical spine; no calcareous lamina; large suberect 

 avicularia distributed amongst the cells on distinct 

 areas, with curved and pointed mandible, directed up- 

 wards. Ocecia prominent, subglobose, rather shallow, 

 strongly frosted. 



Colonies forming a delicate pearly-white lacework. 



