REPORT ON THE ALC YON ARIA. 117 



calyces the spicules consist of tlucc-rayed stars, with intervals l)et\veen the points of the 

 rays of 0"21 and 0'25 mm. 



The foliar expansions of these spicules are chiefl}' two, which form an acute an^le 

 with one another, and have a height of 0'2 and 0'13 mm. The colleret is formed 

 of curved roughened spindles of 0'2G mm. in length, and 0'04 mm. in breadth ; those 

 forming the operculum are flat, with marginal Ijranching spines, truncated at one 

 extremity, and more pointed at the other ; 0'47 in length and 0'07 mm. broad. The 

 axis is horny, l)rown, not longitudinally striated, sliglitly flattened on the stem portion, 

 it is flexible in the slender branches, and soft. The colour of the .stem in spirits is 

 brown. The oral regions of the polyps are of a violet hue, owing to a corresponding 

 coloration of the spicules of the colleret and of the opercular region. 



Habitat. — Station 232, the Hyalonema-gvowml, Japan ; depth, 345 fathoms ; 

 bottom, green mud. 



2. Acomiotogorgia alternans, n. sp. (PI. XXIII. fig. 6 ; PI. XXVII. fig. 4). 



The colony consists of a low and slightly Ijranched little stem, 90 mm. in height, 

 somewhat flattened, which gives off" branches on Ijoth sides, at angles of from 7{f to 80', 

 which are a^'ain furnished with simijle unliranched twio-.s. The branches either wo 



O 1 o o 



straight off" from the stem, or bend after a little upwards, and then proceed parallel to 

 the principal stem. The length of the largest branches is 50 mm.; of the simple 

 branches 15 mm. The diameter of the chief stem at its base is 3 mm. ; of the larger 

 branches To mm. The terminal branches become thickened towards the apex ujj to 

 2 mm. in diameter. The coenenchyma is thick and rough. The polyps are sparsely 

 scattered on the stem ; they are more closely placed on the liramdies and twigs ; they 

 stand at right angles to the stem, at opposite sides, in alternating series, and at 

 intervals of from 1 to r5 mm. At the apices they ai-e closely crowded. The form of 

 the polyp calyx is that of a blunt cone. The diameter of the base is 1 mm., the height 

 1 mm. The opercular region is low and conical. The spicules of the coenenchyma and 

 polyps are alike, as in the fonner species. In the coenenchyma they are more spiny, 

 and there are curved spindles, frequently with foliar prominences. Length 0*3 ; 0'21 ; 

 0"4 mm., with a diameter of the .spindle of Q-QG ; 0'08 ; 0'023 mm. In the calyx 

 there are triradiate spicules, with the thii'd ray shortened, and with a bifoliar 

 appendage with dentate margins; the rays measure 0'33 ; 0'38 ; 0"3 ; 0'16 mm.; 

 height of the foliar expansions 0'16 ; 0"25 ; 0'22 ; 0'23 mm. ; long diameter of an 

 expansion 0'16 ; 0'25 mm. The colleret contains long curved spicules with few spines, 

 of 0-5 mm. in length, and 0"04 mm. in breadth, and 0-46 long by 0'044 mm. broad. The 

 opercular spicules are flat, spiny, armed at one end with smooth projections, towards the 

 other they are more pointed ; they are 0'39 mm. long by O'OG mm. broad. 



