376 Rev. T. Hincks's Contributions towards 



XL VI. — Contributions towards a General History of the 

 Marine Polyzoa. By the Rev. Thomas Hincks, B.A., 

 F.R.S. 



[Continued from p. 92.] 

 [Plates XVI. & XVII.] 



II. FOREIGN MEMBRANIPORINA [continued). 

 Membranipora tenella, n. sp. (PI. XVI. fig. 7.) 



Zooecia elongate, tapering off gradually below ; aperture 

 oval, more or less elongated, occupying (usually) three fourths 

 of the front of the cell, with a narrow and smooth margin, 

 except at the bottom, where it is slightly expanded and punc- 

 tate, covered in by a delicate, translucent and shining mem- 

 brane ; lower portion of the cell tapering slightly downwards, 

 smooth and glossy, with a single nodule in the centre, or two, 

 one on each side. Avicularia none. Ooscia (?). 



This species presents no very striking features. The whole 

 zoarium is of singularly delicate material, and very bright and 

 hyaline. The zooecia vary somewhat in shape, having the 

 aperture at times much elongated and narrowed ; they are 

 disposed rather irregularly in lines. Cells are of frequent 

 occurrence which give origin at the upper extremity to two 

 abnormally narrow ones, the result of a longitudinal division 

 of the bud. 



Loc. Florida, on weed (Miss Jelly). 



Membranipora Flemingii, Busk, var. 

 (PI. XVI. fig. 8.) 



Zooecia turbinate ; area enclosed by a raised margin, cre- 

 nated on the inner surface, occupying three fourths of the 

 front of the cell, with a calcareous lamina, minutely pitted, 

 which fills in about two thirds of it ; aperture moderate, 

 markedly trifoliate ; the lower portion of the cell (below the 

 area) of variable size, tapering downwards to a point j an 

 avicularium in the centre of the lower margin of the area, 

 placed transversely, sloping obliquely upwards, with an acute 

 mandible ; avicularian chamber subturbinate. No spines. 

 Ocecia (?). 



Loc. Unknown. On a foreign species of Retepora (Miss 

 Jelly). 



This seems to be a spineless form of the well-known M. 

 Flemingii. The zoarium, in the only specimen examined, 

 is remarkably bright and silvery ; the lower portion of the cell 



