184 Mr. A. W. Waters on Australian Bryozoa. 



has the zocecia subhexagonal, surrounded by a raised ridge, 

 the acute avicularia are placed transversely at the base of the 

 zooecium ; the ovicell has a raised line enclosing an area, as 

 in M. rlemingii, and there do not seem to be any spines ; but 

 in spite of this slight difference from the European species it 

 seems that it should be placed here. It is allied to both M. 

 Flemingii and M. umhonata, B., but is a larger form than 

 either, the zocecia being about 0*5 millini. wide and the 

 opesia 0*3 millim. 



Log. Of typical minax. Shetland ; Greenland ; Finmark ; 

 Bergen; Capri {A. W. W). Fossil: from the Pliocene of 

 Pruma, Calabria {A. W. W.). 



31. Membranipora tripunctata, Waters. 

 (Ph V. figs. 12, 18, 19, 20.) 



Membranipora tripunctata, Waters, Quart. Journ. Geol. Soc. vol. 

 xxxviii. p. 262, pi. ix. fig. 35. 



Zoarium cylindrical, about 1 millim. in diameter, articu- 

 lated by means of numerous chitinous tubes given off from the 

 front of the zocecia near the articulation. The zocecia have 

 a prominent border, and usually an oval opesial opening in 

 the middle of a calcareous lamina, in other cases nearly the 

 whole of the front of the zooecium is open. 



Except in the ovicelligerous cells there is a wide depressed 

 area above each zooecium, and above this, or above the ovicell, 

 are two narrow avicularia directed diagonally downwards. 

 Specimens from Holborn Island, which are the best preserved, 

 have a fornix on each side (attached to the middle of the side 

 of the zooecium) , widening towards the end, and nearly meet- 

 ing over the aperture ; above these on each side is a club- 

 shaped spine. There are also large raised triangular vica- 

 rious avicularia. The ovicell is smooth and considerably 

 raised, with a circular border below the avicularia. Two 

 rosette-plates near the base of the lateral wall. 



The zooecial characters are truly Membraniporidan and the 

 fornices and spines may be compared with those of M. cor- 

 nigera. 



If it is not called MembroMipora then it would be Foricula, 

 d'Orb., and part of Foveularia^ Busk (Chall. Rep.), would also 

 have to be brought under the same genus ; for although that 

 is defined as having one avicularium yet there are so many 

 instances in which Membraniporce have one or two avicularia 

 in different parts of the same specimen that this cannot, in 

 numerous cases, be considered of any specific value. 



This and Foricula aspera^ d'Orb. (Pal. Fran^. p. 659, 

 pi. 742. figs. 1-5), from the Cretaceous are allied. 



When I gave the specific name I had overlooked the fact 



