98 Descriptions of Neiv, or Little Knoivn, Polyzoa. 



Family, DiSCOPORELLiD^:. 

 Favosipora, n. genus. Plate II., fig. 4. 



Zoarium adherent, raised at intervals in irregular, elevated, 

 rounded ridges, with a distinct lamina. Cells large, of 

 unequal size, closely packed, prismatic. 



F. rugosa, n. sp. 



Forms small, crustaceous expansions, growing on a lamina 

 like Discoporella. The zoarium is composed of large, closely 

 set, prismatic cells. Their openings vary in shape, and also 

 a good deal in size, but there is no structural difference 

 between the largest and smallest. There are usually 

 some irregular, elevated ridges, sometimes obscurely parallel, 

 on different parts of the zoarium. In some cases the cells 

 open all over these elevations, but frequently, especially in 

 the higher, the sides are smooth, the cells opening only on 

 the summit. Some of the cells are closed by a punctate or 

 perforated calcareous membrane, confined to a single cell, or 

 spreading over a number, as in the specimen figured. I 

 cannot detect any spines in the interior of the cells. 



This genus is evidently allied to Densipora corrugata, 

 and there can be no doubt that they belong to the same 

 family as Discoporella. On a fragment of stone I have two 

 small, nearly discoid, specimens, which are forcibly sugges- 

 tive of some forms of D. raxliata. 



Note on Diplopora. 



When I proposed the genus Diplopora for Mr. Hutton's 

 Membranipora cincta, I was not aware that the name had 

 already been used, and I would therefore now alter it to 

 Diploporella. 



EXPLANATION OF FIGURES. 



Plate I. 



'Fig. 1. Cellar ia rigida, natural size. Fig. la. Portion of a 

 branch, magnified. Fig. lb. Group of cells and an 

 aviculariurn, replacing a cell. Fig. lc. Three cells, 

 showing ovarian pores in two. Fig. Id. Single cell, 

 showing the intra-oral denticles. 



