REPORT ON THE POLYZOA, 
63 
§ a. simplices. 
(1) Membranipora cdbida (?), Hincks (PL XY. fig. 4). 
(?) Membranipora albida, Hincks, Ann. and Mag. Nat. Hist., ser. 5, vol. vi. p. 81, pi. x. fig. 5, 
1880. 
Character. — Zoarium very delicate, lace-like, closely adnate (on a Cellepora). Front 
oval, border thin, beaded or subcrenate. Avicnlaria adventitious, placed at the bottom 
of the front of a zooecium, oblique, with a much raised beak. Ooecia small, cucullate, 
surface finely granular. 
Habitat. — Station 172, Off Nukalofa, Tongatabu, 18 to 20 fathoms, coral mud. 
Station 75, lat. 38° 37' N., long. 28° 30' W., 450 fathoms, volcanic mud. 
[Singapore, on Tubipora musica, Hincks.] 
The very close resemblance of this form to that described by Mr. Hincks leaves 
little room for doubt as to their identity ; the chief point of difference appears to be 
the larger size of the avicularia in Mr. Hincks’ form. 
(2) Membranipora crassimarginata, Hincks (sp.). 
Var. a. erecta (PI. XIV. fig. 3). 
Character. — Zoarium foliaceous, expanded. Zooecia quincuncial or irregularly serial, 
contiguous or discrete. Front regularly oval, entirely membranous. Margin rounded, 
granular. Avicularia vicarious ; smaller than the zooecia, with a large broadly spatulate 
mandible pointing directly upwards. Ooecia ? 
Habitat . — Station 162, off East Moncoeur Island, Bass Strait, 38 to 85 fathoms, sand, 
shells. Station 151, Off Heard Island, 75 fathoms, volcanic mud. 
Var. b. incrustans (PI. XV. fig. 5). 
Membranipora crassimarginata, Hincks, Ann. and Mag. Nat. Hist., ser. 5, vol. vi. p. 71, 
pi. ix. fig. 1. 
(?) Biflustra lacroixii, Smitt, Florid. Bryoz., pt. ii. p. 18, pi. iv. figs. 85-88. 
Character . — Zoarium adnate (upon shell). Avicularia usually of equal size with the 
zooecia. Border sometimes thicker. 
Habitat . — Station 135c, off Nightingale Island, Tristan da Cunha, 110 to 150 fathoms. 
[Madeira — J. Y. J. teste, Hincks ; Gulf of Florida — Pourtales, 13 to 60 fathoms.] 
The only difference between the form here described and that noticed by Mr. Plincks 
in Mr. J. Y. Johnson’s collection from Madeira, consists in the apparently more robust or 
coarser structure of the latter. In the Challenger specimens (very few, however, in 
