8 Rev. T. Hincks on tne 



The ocecium was not observed on Californian specimens, 

 but is present in profusion on those from the Queen Charlotte 

 Islands, It is shallow, cucullate, smooth, and closed in front 

 by a chitinous operculum. The species forms brown or red- 

 dish-brown patches. 



Membranipora variegata, Hincks. 



Dolomite Narrows, in about 8 fms., very plentiful ; spreading 

 in large patches over the surface of shells. [California.] 



Specimens occur in which there are two of the pedicellate 

 avicularia at opposite sides of the cell, instead of the normal 

 one. The spines are without the dark-coloured base, which is 

 a conspicuous feature in the. Californian form. 



Memhram])ora aeifera^ MacGillivray, form rmiltispinata. 



(PI. XIX. fig. 4.) 



The form from the Queen Charlotte Islands which I refer 

 to MacGillivray's species differs in some respects from his 

 description ; but the two agree so perfectly in the most striking 

 and important characters that there is hardly room for doubt 

 as to their identity. He describes his M. acifera as having 

 " one or two sharp incurved spines on each side, and usually 

 a small round spine in each upper angle." In the North 

 Pacific specimens, which are finely developed, there are two 

 erect and pointed spines at the top of the cell, and along each 

 side six or seven rather tall, straight, acuminate spines, which 

 slope inwards without meeting. The spines are at best a 

 somewhat variable character ; and the single specimen which 

 MacGillivray examined can hardly be accepted as fixing the 

 normal armature of his species. The general character and 

 the remarkable avicularium are the same in both forms. 



Virago Sound. [Victoria [MacGillivray).^ 



Membranipora echinus^ n. sp. (PL XIX. fig. 5.) 



Zooecia quincuncial, oval, distinct, separated by rather deep 

 and wide interspaces ; front wall wholly membranous ; two 

 spines at the top and from seven to eight slender, closely set, 

 pointed, and rather tall spines down each side, which slant 

 inwards but barely meet in the centre ; on each side, springing 

 from behind the second spine from the top, a pedicellate avicu- 

 larium, the upper part large and much swollen (closely re- 

 sembling a "bird's head"), very slightly hooked at the 

 extremity, borne on a very thin pedicle ; mandible slender, 

 pointed. Ocecium (?) . 



Loc. Houston Stewart Channel ; Curashewa, 20 fms. 



