MR. A. W. WATERS ON MEMBRANIPOEIDJE. 



67r 



Membi.anii'oba nitens, HincTcs. (PL 48. figs. 3, 4, 5.) 

 M. m:ens has a comb-like process borne on a broad stalk 

 which jrojects downward into the zooeciura, and this is referred 

 to when dealing with the pair of fringed processes in 

 M. tehuelcha. 



Membranipora mabeeensis, sp. nov. (PL 48. fig. 19.) 



Zoarium incrusting, with tendency to form separated lines of 

 cells. Zooecia oval, slightly produced below the area; opesia 

 oval, margin raised, very thick, sloping inwards. Six oral spines ; 

 usually five delicate marginal spines. Avicularia vicarious, with 

 an aviculai'ian chamber resembling in the lower part an ordinary 

 zooecium, but with fewer spines. The distal end of the avicula- 

 rian chamber is raised and serrate ; in this is situated the large 

 semicircular mandible, on which a dark curved line forms a small 

 arc. The ovicell has a rib, and on the ovicellular zooecia there 

 are two oral spines. 



This in most characters corresponds with a common form from 

 New South Wales which I consider is M. corhida (PL 48. fig. 20), 

 but in that the six oral spines are much stouter and the marginal 

 spines are more numerous. It is extremely probable that JuUien 

 had a specimen of this species before him when he described 

 M. tenuis, but the spines had been lost. He speaks of only one 

 zocBcium being intact. 



Loc. Madeira {J. Y. Johnson'' s collection). 



MEMBRATflPORA SOELETOS {BusTc). (PL 49. figS. 2-6.) 



Lepralia sceletos, Busk, Quart. Journ. Micr. Sac. voL vi. p. 262, pi. xx. 

 fig. 3. 



Membranipora sceletos, Hincks, Ami. Mag. Nat. Hist. ser. 5, vol. vi. 

 p. 73. 



It is impossible to give a figure faithfully representing this 

 extremely beautiful species, as under the microscope we are 

 looking down upon the narrow edge of the flattened spines. I 

 hope, however, that my figure will explain the " pedunculated 

 plate " at each side of the aperture, also the way in which the 

 spines when they meet in the middle bend aside instead of 

 ankylosing in the central line. It will be seen from figs. 3 and 

 4 that the pedunculated plate is divided at the top, forming two 

 or three lobes. This looks like the commencement of a cervicorn 

 process. The avicularia and the mandibles are very similar to 

 those of M. flustroides (PL 49. fig. 12). 



Loc. Madeira. 



LINN. JOURN. — ZOOLOGY, VOL. XXVI. 48 



