47 



Acamptogorgia hehnjcoides, von Koch, var. rohv.sfa, n. 



,, circiimi, n. sp. 



Acis spinosa, n. sp. 

 Muricella hengalensis, n. sp. 



Acanthog-orgia aspera, Pourtales ( =A. spinosa, Hiles?). Plate II. fig. 2 ; 



Plate V. fio-. 15. 



This species is represented liy two beautiful specimens, 185 mm. and 120 mm. 

 in height. 



The colony is branched in one plane, the branches being in some parts alter- 

 nate, in other parts quite irregular. The polyps are densely crowded on the stem and 

 branches, giving each l^ranch a bottle-brush appearance. At the base there is a 

 flat and thin disc of attachment. Very light brown is the general colour, but tlie 

 polyps are almost white. In the larger specimen the axis has a l)asal diameter of 

 over 1-5 mm., and is flattened in the plane of branching from a point a short 

 distance above the base. In the smaller specimen one surface is flattened and 

 marked by a broad shallow groove, while the opposite surface is rounded. This 

 flattening is not so marked in the branches, and some of the terminal branches or 

 twigs are almost cylindrical. The surface of the axis is marked by a large number 

 of discontinuous longitudinal ridges. 



The polyps are arranged all over the stem and branches ; they are long, up 

 to 6 mm. in height, with a basal diameter of about TS mm. They are almost 

 cylindrical, with a tendency to expand slightly near the oral end. They stand at 

 right angles to the stem and branches, and are firm and rigid. 



On the polyp body the spicules are arranged in eight rows, each showing sharp 

 projecting points formed by the free ends of the spicules. The spicules of each 

 row are arranged in pairs, each pair converging and forming an inverted V with 

 the apex directed towards the mouth of the polyp. The spicules of each V are 

 slightly curved outwards at the lower end, so that they pass over to, and interlace 

 with, the basal portions of the spicules of the adjacent V on each side. Towards 

 the apex of each row the spicules become slightly smaller, and then the row ends 

 usually in three projecting overlapping spines, one markedly larger and stronger 

 than the other two. Thus the apex of the polyp is surrounded by a number of 

 points which project a considerable distance beyond the infolded tentacles. 



The spicules on the aboral surface of the infolded tentacles form a flat eight- 

 rayed operculum. On each tentacle they are arranged at first longitudinally in 

 the middle line with spicules on the sides at right angles to those in the middle, 

 then the median spicules fail and the side spicules form Vs which become 

 gradually shallower until the spicules lie transversely and alternate with ftne 

 another. 



The coenenchyma is thin, and is densely packed with spicules. The .spicules of 



