Membranipora, Blainville. 



M. membranacea, Linn. sp. Brighton, Robe. 



M. |;>?Yc^on^«, n. sp. Fig. 1. Zoarium encrusting. Zooecia 

 opposite in regular longitudinal and transverse series, very large, 

 much longer than broad, separated by narrow raised lines; upper 

 extremity arched and thickened ; no spines or processes. 



This is an exceedingly delicate species, spreading as a thin film 

 over the surface of a broad leaf of, seemingly, Zostera. The 

 zooecia are very regular in transverse and longitudinal rows, the 

 separating walls being very slender. There are no spines or pro- 

 cesses as in its nearest congener 31. meinhranacea. A curious cir- 

 cumstance is that many of the longitudinal rows consist entirely 

 of aborted zooecia, which are of the same length as the others, 

 but are narrower, destitute of mouth, and have the transverse 

 separating partitions straight and very thin. In many of these 

 there is a white shining fibrous bundle, the nature of which is 

 not apparent ; it may be parasitic. 



Mr. Smeaton informs me that this was found at Wallaroo by 

 Mr. O'Halloran. 



M. corhula^ Hincks. Robe. 



Amphiblestrum, Gray. 



A. m-genteuin, McG. (Lepralia trifolium, McG.) 



A. cervicorne, Busk. 



BiFLUSTRA, D'0rbig7iy. 



B. jugcdis, n. sp. Figs. 2 and 2a. Zoarium crustaceous. 

 Zooecia alternate, in regular lines, elongated, quadrate ; margins 

 thick, granular ; upper margin thick, with a short blunt process 

 at each end ; anterior surface for a large extent strengthened by 

 a very thin, slightly granular, calcareous layer. 



Of this there is only a single small specimen. The anterior 

 thickening of the surface is very indistinct, and I am. not satisfied 

 that it should not rather be referred to Membranipora. 



FAMILY MICROPOHID.E. 

 Thairopora, McG . 

 T. dispar, McG. Brighton. 



DiPLOPORELLAj McG. 



D. cincta, Hutton, sp. Brighton. 



MiCROPORA, Hincks. 

 M. coriacea, Esper., sp. Glenelg. 

 M. p)erforata, McG. Robe. 



