ME. A. W. WATERS ON MEMBEANIPOKID^. 687 



I should not unite it to M. Dumerilii : in fact it only seems sepa- 

 rated from M. coronata by tlie avicularium not being long and 

 winged, but short and triangular, corresponding with Hinck's 

 first description of M. coronata. The avicularium of M. coronata 

 is, however, set very far back, which is not the case with M. in- 

 crustans. It reminds us of M. levata, Hincks (which has since 

 been described by MacGrillivray* as Bifliostra sericea), but that 

 has thin walls, whereas in M. incrustans the walls slope in- 

 wards. 



Loc. Station 135 a : off Inaccessible Island, Tristan da Cunha, 

 75 fathoms (' Challenger'). 



Membeafipoka aemata {Hasivell). (PI. 47. fig. 3.) 



Biflustra armata, Hasivell, " On some Polyzoafroyn the Queensland Coast,'' 

 Proc. Linn. Soc. N. S. Wales, vol. v. 1880, p. 38, pi. i. fig. 7. 



Membranipora panhoplites, Ortmann, " Die Japanische Bryozoenfauna,' 

 Arch.f. Naturgesch. 1890, vol. i. p. 28, pi. ii. fig. 4. 



A specimen from Port Molle, Australia, was sent to me marked 

 M. nigrans, Hincks. It is bilaminate, and on the side-walls there 

 are numerous rosette-plates. The M. panhoplites of Ortmann is 

 described and figured with the avicularia in the lower part of the 

 cell, but it is easy to take the avicularium on the distal part 

 of one zocecium as belonging to the proximal part of the next ; 

 and as specimens in the British Museum from Japan marked 

 "Ji.paw/io^ZzYes" have the avicularia in the distal part, I think 

 we may take it that this is usually the case. 



Loc. Port Denison, Holborn Island, 20 fath. (Hasivell) ; Port 

 Molle ; Sagamibai, 40 fath., Japan {Ortmann). 



Membeanipoea hian"s, JSLincJcs. (PI. 48. fig. 16 ; PI. 49. 

 figs. 15, 16.) 



Membranipora hians, Hincks, Ann. 8j- Mag. Nat. Hist, ser, 5, vol. xv. 

 p. 248, pl. vii. fig. 5. 



Membranipora Cyclops, Busk, Cat. Mar. Polyz. p. 61, pl. Ixv. fig. 3. 



The expansion of the operculum beyond the chitinous ridge 

 (Pl. 48. fig. 16) is characteristic, and the upper part fits on to a 

 small shelf on the distal border of the zocecium. The M. cyclops 

 of Busk has been united by various writers to several other 

 species ; but a second comparison of the British-Museum specimen 



* "New or Little-known Polyzoa," pt. xiii. 1889, Proc. Eoy. Soc. Vict. 

 Q. s. vol. ii. p. 107, pl. V. fig. 1. 



