A MONOGRAPH OP THE TERTIARY POLYZOA OP VICTORIA. 39 



15. M. papyracea, n.sp. PL V., fig. 8. 



Zoarium thin, unilaminate and probably encrusting. Zooecia quincuncial, 

 hexagonal but with the upper angles rounded off, separated by very narrow raised 

 margins ; a broad, very thin and slightly granular lamina sloping inwards ; 

 membrane covering the aperture membrano-calcareous, but very thin. 



B.R 



A very delicate species, distinguished by its papery appearance. Parts of the 

 covering membrane are preserved in all the zooecia as an excessively thin calcareous 

 layer. 



16. M. perfragilis, McG. PL V., figs. 10, 11. 



Biflustra perfragilis, McG., P.Z.V., 57; Membranipora id. Hineks, A.M.N. H., 

 Oct. 1884. 



Zoarium bilaminate, thin. Zooecia elongated, rounded above ; aperture 

 occupying about four-fifths of the area, elliptical, its margins thickened and very 

 finely granular ; the lamina confined to the lower part of the area ; avicularia as 

 long as, but narrower than the zocecia which they replace, slightly contracted at 

 the base of the mandible, which is long, broad and directed upwards. 



M.C. A common living Australian species. 



17. M. gregsoni, n.sp. PL V., figs. 12, 13, 14. 



Zoarium bilaminate. Zooecia large, very deep, rounded or elliptical ; margins 

 thick, rounded, finely granular; avicularia small, transverse, with long setiform 

 mandibles, situated on large bullate processes at the base of the zooecia. 



M.C. ; B. ; B.U. 



At once distinguished by the very peculiar avicularia. These are situated on 

 large bullate projections at the bases of the zooecia ; the basal portion is very small, 

 and there is a long narrow fissure, seemingly for the lodgment of a setiform 

 mandible, extending transversely to one side. When the front of the bullate 

 process is worn off, as is usually the case, there is left a large circumscribed cavity, 

 the real nature of which would be unintelligible without a knowledge of uninjured 

 specimens. Occasionally, in addition to the vibraculoid avicularia, there are other 

 short and broad avicularia projecting into the bases of the apertures of the zooecia. 



I have much pleasure in dedicating this species to Mr. Gregson, to whom I am 

 indebted for the material I have examined from Bairnsdale. 



