288 Rev. T. Hincks's Contributions towards a 



Flustra nohilis, sp. u. (PI. VI. figs. 5.) 



Zoarium foliaceous, of a dark brown colour, margin 

 slightly lobate, attached bj a dense mass of delicate fibres, 

 which originate on the lower series of zooecia, and are given 

 off in pairs (one on each side) or singly from the oral extre- 

 mity of the cell. Zooecia on one sm'face only, quincuncial, of 

 large size, elongate, wide above, narrowing downwards (sub- 

 pyriform), each one overlapping more or less the zooecium 

 immediately above it ; margin well raised, bearing a con- 

 tinuous line of bifid spines along the sides, at the summit 

 four short spines, the two central ones usually larger than the 

 rest, area occupying the whole front surface and closed in by 

 a very stout, shining membrane ; orifice ample, placed at the 

 top of the area and extending from side to side, arched above, 

 the lower margin straight, breadth much exceeding the 

 height, operculum convex, with a thickened rim around the 

 top and sides. Avicularia borne on the dorsal surface of the 

 zooecia at the upper extremity (where it overlaps the neigh- 

 bouring cell), placed one on each side, erect and free, mem- 

 branaceous, tumid above, and tapering downwards to the 

 point of attachment, on the summit a semicircular mandible 

 (PI. YI. fig. 5 h). Ooecium (?). 



Loc. Port Elizabeth, South Africa {^Hss Jelly). 



This is a handsome species and exhibits some interesting 

 peculiarities. The zooecia are of unusual size, and, where 

 furnished with the forked lateral spines, present a very 

 picturesque appearance. The spine is composed of a short 

 upriglit piece, from the base of which springs a tall slender 

 fork, which bends inwards over the area ; the latter is fre- 

 quently broken oft', and the margin of the cell is occupied by 

 a line of denticles. 



The membranous covering of the area is remarkable for its 

 stoutness and its shining surface. The operculum marks an 

 advance on the small membranous lid which usually closes 

 the orifice in this family. It is of large size, filling in the 

 upper portion of the area, and is strengthened by a well- 

 marked rim round the top and sides. Below it is continuous 

 with the membranous wall, and its limit is marked by a mere 

 line. It is in some measure a transitional form between the 

 simpler structure and the isolated and hinged operculum of 

 the Flustrine genus Euthyris and the higher Cheilostomata. 

 The avicularium oi Fhtstra nohilis is of quite a different type 

 from that which prevails in the genus to which it is referred. 

 The ordinary Flustrine avicularium is very slightly 

 specialized ; the mandibular apparatus is commonly placed 



