Polyzoa of Queen Charlotte Islands. 9 



A very marked characteristic of this species (which belongs 

 to the M. spinifera section) is the distinctness of the zooecia, 

 which lie so much apart from one another that the whole cell 

 to its very base is visible, the wall flanging outward slightly 

 below. It is very common amongst the dredgings. 



Memhraniyora exilis^ n. sp. (PI. XX. fig. 1.) 



Zooecia very regularly quincuncial, oblong, slightly en- 

 larged about the middle, subtruncate above and below, set closely 

 together, of considerable size and delicate half membrana- 

 ceous material ; margin thin, a good deal raised, the front wall 

 wholly membranous ; at the top of the cell two pointed spines, 

 and (usually) two on one side and three on the other situated 

 in the upper half of the cell, slender, acuminate, erect, jointed 

 to a tubular base ; a sessile avicularium on the margin at one 

 side (often wanting) just below the top ; beak much swollen 

 below, inclined upwards, scarcely bent at the extremity ; 

 mandible blunt, directed downwards. Ooeciuni (?) . 



Loc. Houston Stewart Channel, enveloping (7e?/a/'^a&orea?^s, 

 Busk, with a very thin crust. 



Membranipora Sophue, Busk, form matura. 

 (PhXX. fig. 2.) 



Zocecza oval, quincuncial, set very closely together; front wall 

 wholly membranous ; margin thin, smooth, on each side from 

 four to six sharply pointed spines, which bend rather abruptly 

 over the area and meet in the middle ; an avicularium at each 

 side on the margin, just below the upper end, slightly raised, 

 pointed, the mandible directed upwards, a small erect spine 

 at the base of each avicularium ; at the bottom of the cell a 

 single avicularium^ with an elongate triangular mandible, 

 variously turned (sometimes two). Ocecwwi rounded, smooth, 

 with a rib arching across the front, frequently carried up into 

 a peak. 



Loc. Houston Stewart Channel. [Assistance Bay ; Spitz- 

 bergen.] 



Described as M. conferta ('Annals' for September 1882). 

 I am now convinced that it is a form of M. Sophice. Smitt 

 notices intermediate varieties. 



Membranipora nigranSy n. sp. (PI. XIX. figs. 2, 2 a.) 



Zooecia large, ovate (variable in shape, sometimes arched 

 above and narrowing downwards, sometimes broad-ovate, 

 sometimes oval), irregularly disposed ; margins much ele- 

 vated, crenate, tlie whole front of the cell covered by a rather 



b 



