8 Mr. A. W. Waters on Australiayi Bryozoa. 



mandibles in decalcified specimens, and the apertures in the 

 avicuharia of Invershda nutrix are of the same shape. The 

 operculum of /. nutrix is very thick round the border, re- 

 minding lis of the operculum of Dijyorula verrucosa. 



Although specifically very distinct, Jullien's species from 

 South America and mine from New South Wales seem to 

 fall into the same genus, and probably the New South Wales 

 species will have to be called Invershda inversa. I am now 

 unable to understand why I placed mine with Porina, but 

 when describing it said that I thought it would have to be 

 made the type of a new genus. 



Micropora elongata^ Hincks. (PI. I. figs. 21, 22.) 



Steganoiwrella ehnr/ata, Ilincks, Ann. & Mag. Nat. Hist. ser. 5, vol. vi. 



p. 380, pi. xvi. %. 4. 

 Micropora variperforata, Waters, Quart. Joxmi. Geol. Soc. vol. xliii. 



p. 51, pi. viii. fig. 27. 



From Green Point there are a few zooecia in shape and every 

 particular exactly resembling IMr. Hincks's figure and descrip- 

 tion of S. elotigaia ; but on the same shell there is another 

 colony in which the surface has numerous similar large 

 perforations (opesiules) and similar avicularia, but the 

 zooecia shorter and wider. In the more typical specimens 

 there is a well-marked " opesiule " at each upper corner, but 

 in some cases it cannot be made out, and in others there are 

 more than one on each side. 



The number of opesiules has been shown to be variable in 

 this and in Micropora lejnda^ Hincks. Dr. Jullien, however, 

 would use the form of the opesiules as the chief generic cha- 

 racter, making out of the MicroporidaB the genera Gargantuan 

 J., Calpensia, J., Andreella, J., JVoodipora, J,, Verminariay 

 J., Peneclausa, J., TlialamojjoreUaj Hincks, Manzonella^ J., 

 Pergensia^ J., Setosella, Hincks. Surely genus manufac- 

 turing never has gone and never will go further than this ; 

 and as Dr. Jullien has called attention to many anatomical 

 points of importance, it is much to be regretted that he should 

 be so hasty in his generalizations on classification. 



In its typical form this does not seem at all like M. coriacea ; 

 but when a series is examined there is found to be little 

 ditFerence. In older cells of M. coriacea the surface of the 

 front wall seems almost closed, whereas in the younger zooecia 

 the perforations are distinctly seen, and in some zooecia of 

 M. elongata the pores are not large and distinct. 



