ME. A. W. WATERS ON MEMBEANIPOEID^. 691 



larium on the area below the zooecium is nmcli larger than tlie 

 others and raised. The depressed opesia is nearly ova], but 

 straigbter on the lower edge, witb the margins slightly crenulated. 

 The' opesia is depressed in the same way in M. occuUata, Waters, 

 M. Mans, Busk, &c. Tbe solid ovicell is not mucb raised, and 

 an area is marked off by a line near tbe distal end. There are 

 numerous distal rosette-plates and eigbt lateral ones. 



Tbis is very closely allied to M. {Foveolaria) tuhigera, B,, as 

 in botb tbe opesial opening is in pize and sbape about the same ; 

 tbere are in botb numerous small avicularia, and frequently a large 

 one below the opesia. The broad smooth ovicell is similar in botb. 

 as are also the lateral and distal ro.-^ette-plates, but in the present 

 species the lateral tube ("articulated process") is wanting, and 

 no trace of any such structure has been found. In M. tubigera 

 tbere is on the border, opposite to tbe tube, an irregular process, 

 which is wanting in the M. elizahethiensis, though sometimes the 

 border carries small irregular elevations. The general appearance 

 varies much between tbe older and younger zooecia. 



Loc, Port Elizabeth. 



Membeanipoea tripunctata, Wafers. (PL 49. fig. 18.) 



Membranipora tripimctata, Waters, Quart. Journ. Geol. Soc. vol. xxxviii. 

 p. 262, pi. ix. fig. 35 ; Ann. ^ Mag. Nat. Hist. ser. 6, vol. xx. p. 184, 

 pi. V. figs. 12, 18, 19, 20. 



I am now able to give a more satisfactory figure of this species, 

 through having made an examination of a specimen boiled in 

 caustic potash. Tbe spaces above tbe zocecium are avicularian 

 chambers. This was first described from a small fossil specimen, 

 of which the state of preservation was not very good, and as soon 

 as others are found they should be examined in order to test 

 whether I was right in uniting the recent and fossil forms. 



Loc. "N.E. Australia"; Holborn, Brougbton, and Fitzroy 

 Islands (Queensland). 



EXPLANATION OF THE PLATES. 

 Plate 47. 



Fig. 1. Memhranij>ora ffregaria, ILeller. X 25. 



2. Membranipora curvirostris, Hincks. Avicularia. X 50. 



3. Membra,nij)ora armata, Haswell. Avicularia. X 50. 



4. Membranipora crassimarginata, Hincks. Naples. X 25. 



