General History of the Marine Polyzoa. 279 



species to Biflastra, as I am unable to find anj valid distinc- 

 tion between that genus and Menhranipora. 



Family Cribrilinidse. 



Cribrilixa, Graj. 



Gribrilina monoceros, MacGillivraj. (PI. VIII. fig. 5.) 



I have figured a very young colony of this species from 

 Port Phillip Heads, which exhibits in its perfect simplicity a 

 striking contrast to the adult condition. The mature cell is 

 remarkable for the number and variety of the appendages 

 with which it is furnished. 



Family Poriuidse. 



PoiUNA, D'Orbigny. 



Porina niayiiirosfrisj MacGillivray (sp.). 

 (PI. IX. fig. 6.) 



Lejiralia magnirostris, MicU. Proc. Royal Soc. Victoria, 1882, " De- 

 scriptions ofuew or little-known Polyzoa," part ii. 



I cannot hesitate, looking to the many points of similarity 

 between the two forms, to identify AlacGiUivray's Lepralia 

 maynirosfr is with a Porina which occurs abundantly amongst 

 Mr. Wilson's dredgings. He does not note the characteristic 

 "special pore," but in other particulars there is complete 

 agreement. The habit is Hemescharine, and the celliferous 

 lamina is very stout and strong; it is twisted and sinuated 

 and forms large chambered masses of a yellovvish-brown 

 colour. The pore is sometimes placed a good way down the 

 ceil, sometimes it is much nearer the orifice; it is raised and 

 tubular. The whole zoarium is usually covered with an 

 epidermal investment, which renders it ditficult to make out 

 the structure. The figure represents a young marginal cell 

 and the avicularium of the cell below it. 



Family Cyclicoporidae. 



Zocecia having the front wall wholly calcified and destitute 

 of raised margins or depressed area, with a more or less 

 orbicular orifice. 



Cyclicopora, n. gen. 

 Generic character. — Zocecia with a perfectly simple orifice 

 more or less orbicular. Zoarium (in the only known species) 

 incrusting. 



Cyclicopora proilonga^ n. sp. (PI. IX. fig. 7.) 

 Zocecia (usually) of great length and of about equal width 



