a General History of the Marine Polyzoa. 81 



II. FOREIGN MEMBRANIPORINA. 



Family Membraniporidae. 



Membranipora, Blainville. 



a. Species with a membranous front wall. 



Membranipora albida, n. sp. (PI. X. fig. 5.) 



Zooecia set closely together, oval, wholly membranous in 

 front; border crenate, with a somewhat sharp edge or margin, 

 destitute of spines. Avicularia numerous, scattered over the 

 zoarium, placed in somewhat rectangular hollow spaces 

 amongst the cells, which they partially fill ; base of avicula- 

 rium depressed, the beak raised, curved towards one side, 

 extending to the top of the hollow (or avicularian cell), 

 traversed by a narrow central groove ; mandible expanded 

 and somewhat crescentic at the base, above slender, curved, 

 spine-like. Ooscium small, shallow, subarcuate, finely frosted 

 (almost smooth). 



Loc. Singapore, on Tubipora musica (Mr. Moore, Liverpool 

 Free Museum). 



This species, of which the avicularium is the most marked 

 feature, is allied to the British M. curvirostris, mihi, from 

 which, however, it is distinguished by the total absence of 

 spines, the form of the ooecium, and the very different charac- 

 ter of the avicularian appendages. 



Membranipora plana, n. sp. (PI. XL fig. 2.) 



Zoacia large, oval, distinct, surrounded by a narrow border, 

 which is rounded and finely crenate, sometimes slightly pro- 

 duced below the aperture and pointed ; front wall wholly 

 membranous, very much on a level with the margin of the 

 cell, so as to give a flattened appearance to the surface of the 

 zoarium. Avicularia scattered, placed in somewhat lozenge- 

 shaped intercellular spaces ; beak elongate, straight, occupying 

 the centre of the area, traversed by a narrow groove which 

 expands towards the lower extremity ; mandible with an en- 

 larged base, above it setiform, slightly curved at the top. 

 Ooecium rounded, rather large, frosted. 



Loc. Australia (Miss Jelly). 



This species and the preceding are really much more dis- 

 tinct than they might appear to be from a comparison of the 

 descriptions. 



A reference to the figures will show the amount of the 

 difference between them. M. plana is specially characterized 

 by the large size of its zocecia and the flatness of its surface. 



Ann. & Mag. N. Hist. Scr. 5. Vol. vi. 6 



