34 A TuoNOGit.vriT or thi': tertiaky tolyzoa op victoria. 



extremity of zocpciiim elevated; usually two siin])le or furcate spines at the anterior 

 extremity, occasionally absent, the anterior cd^c beinc; then wide and smooth ; on 

 the marnin at one side a sessile aviciilariiiin raised on n broad process, the mandible 

 directed anteriorly and the rostrum tcnniuiitiui;' iu a pointed, slightly-curved beak; 

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

 (frequently al)S(>nt), sim])le, furcate or branched. Dorsal surface convex, covei'ed 

 ■with numcM'ous tubercles marking the attachments of the radical tubes. 



S.l'. ; ^l.C. ; ^r. A conunon living Australian species. 



This is a most iuteresting species, marking the transition fi'om Beania (including 

 Diachoris") to Membrani])<)ra. I have previously included it in the former genus, 

 with which it agrees in the disjimction of the zocecia and the (devation of their 

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

 marked approach to the pedunculate foi-ms found in ]V'ania. I now, however, 

 think that ou the whole it has moi'e intimate relation to Membranipora, and I, 

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

 Point specimens there is no ai:>pearance 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. iiilcriiicdin, Kirkpatrick, var. PL lY., lig. 8. 



3Iemhr(i)tipo]'a radlcifcro, var. iiilermedia, Kirkpatrick, Proc. Poy. 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 Avitli tubercles, and having 

 from the lower end a Ini-ge branching, usually ceiwicorn process extending nearly 

 horizontally inwards; tlie s])ines on the opposite margin usually branched. 



M.C. Living. Torres Straits. 



This agrees closely with the form describ(>d 1)y Kirkpatrick, the only difference 

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

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

 cervicorn process. Hincks (A.M.N.H., Dec, 1891, p. 179) suggests that Kirk- 

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

 specimens, hoAvever, are undoubtedly fully develojoed. The avicularia are different, 

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

 the avicidariuna ai"e also more erect and distinct than those by the coalescence of 

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

 specimen they extend OA'cr and beyond the opposite margin. They are of the same 

 nature as the branched processes or spines of the recent Australian J/, cerclcornis 

 (Busk). 



