34 A MONOGRAPH OP THE TERTIARY POLTZOA OP VICTORIA. 



extremity of zooecmm elevated ; usually two simple or furcate spines at the anterior 

 extremity, occasionally absent, the anterior edge being then wide and smooth ; on 

 the margin at one side a sessile avicularium raised on a broad process, the mandible 

 directed anteriorly and the rostrum terminating in a pointed, slightly- curved beak ; 

 on the opposite margin, nearer the oral extremity, is a conspicuous spine or process 

 (frequently absent), simple, furcate or branched. Dorsal surface convex, covered 

 with numerous tubercles marking the attachments of the radical tubes. 



S.P. ; M.C. ; M. A common living Australian species. 



This is a most interesting species, marking the transition from Beania (including 

 Diachoris) to Membranipora. I have previously included it in the former genus, 

 with which it agrees in the disjunction of the zooecia and the elevation of their 

 anterior extremities. The avicularium also, although subsessile and fixed, shows a 

 marked approach to the pedunculate forms found in Beania. I now, however, 

 think that on the whole it has more intimate relation to Membranipora, and I, 

 therefore, follow Hincks in referring it to that genus. In some of the Schnapper 

 Point specimens there is no appearance of the avicularium, while in others from 

 that deposit and Muddy Creek its situation is indicated by a long narrow space in 

 the cell- wall. 



2. M. intermedia, Kirkpatrick, var. PL IV., fig. 8. 



Membranipora radicifera, var. intermedia, Kirkpatrick, Proc. Boy. Dublin 

 Soc, 1890. 



This species differs from the last in the avicularium being more prominent and 

 projecting over the area, the beak being large, covered with tubercles, and having 

 from the lower end a large branching, usually cervicorn process extending nearly 

 horizontally inwards ; the spines on the opposite margin usually branched. 



M.C. Living. Torres Straits. 



This agrees closely with the form described by Kirkpatrick, the only difference 

 being in the larger development of the avicularium, the base of which is also 

 thickly covered with small pointed tubercles, and in the greater extension of the 

 cervicorn process. Hincks (A.M.N.H., Dec, 1891, p. 479) suggests that Kirk- 

 patrick's specimens may be the young state of Hiantopora ferox (McG.). My 

 specimens, however, are undoubtedly fully developed. The avicularia are different, 

 being more prominent and more erect. The branching processes from the base of 

 the avicularium are also more erect and distinct than those by the coalescence of 

 which the perforated front wall of Hiantopora is formed, and in fact in one 

 specimen they extend over and beyond the oj)posite margin. They are of the same 

 nature as the branched processes or spines of the recent Australian M. cervicornis 

 (Busk). 



