478 Rev. T. Tlincks's Contributions towards a 



dale (Gippsland) in which none of tlie cells are acuminate," 

 (Quart Journ. Geol. Soc, Aug. 1882.) 



'Annals,' August 1881 (p. 65 sep.). 



Mucronella i^orosa, sp. n. 



This species niu.st, I think, be considered a form of ^fac- 

 Gillivray's M. Elhrii, as Mr. Waters has suggested *, though 

 there are striking differences between them. The most 

 remarkable feature of J/. Ellerii is the line of spinous pro- 

 cesses with rounded heads situated on the peristome, which is 

 much elevated. These are entirely absent in M. jiorosa^ and 

 the peristome is not raised ; consequently the general aspect 

 of the zoarium in the two forms is strangely dissimilar. As 

 a result probably of the elevated spinous peristome in J/". 

 EUerii the massive central mucro is not developed, and the 

 large avicularium occupies a place some way down within 

 the lower margin. The surface of the cell is more or less 

 covered with nodules distributed amongst the pores. 



J/, porosa is much simpler in character. There is a total 

 absence of the spinous processes ; the centre of tlie lower 

 margin bears a massive mucro, much swollen at the base, 

 on one side of which, turned slightly inward, is placed the 

 avicularium, with a broad rounded mandible. Lar^e spatu- 

 late scattered avicularia are present at times on both forms. 

 In a specimen from Singapore or the Philippines numerous 

 smaller avicularia, elevated above the surface and resemblinir 

 the oral form, are distributed over the cells. 



The cells in M. Elhrii are suberect. The small rounded 

 avicularium on the margin at one side of the mucro is charac- 

 teristic of M. porosa. The latter may stand as M. Elleru\ 

 form 2>orosa. 



M. vultur'f, which ^Ir. Waters would also refer to M. 

 Ellerii, is, I think, entitled to specific rank. Its remarkably 

 large cells, decumbent, not suberect or oblique like those of 

 il/. Ellerii y its exceptionally massive nuiero, its large avicu- 

 larium, with its elongate, finely pointed mandible bent abruptly 

 inward at the top, its large, articulated, oral spines, form a 

 group of distinctive characters. The cells of M. vuitur differ 

 not only in size but in general character from those of M. 

 Ellerii and its form porosa. 



* " Australiau Rrvozoa," ' Annals' f^r September 1S87, p. 104. 

 t " Contributions " &c., p. OS (sep.). 



