13 



This species is easily distinguished from previously described form-; l>v (Ill- 

 immense size of the spieules in the ccenenchyma. 



Whitelegge described Xi/>/i<>in>t/<>i-i/ia macrospina from Funafuti with spimles 

 sometimes 6 mm. in length, and .Miss Miles has described an apparently similar 

 form in which the largest spieules were 4'4xO'.37 nun. (MS. kindly lent by I'm 

 fessor Ilickson). Through Professor Hickson's courtesy we have been ;ililr to 

 examine this specimen, and we find that it is very dili'erent from ours. 



Locality : Station 246 ; 11 14' 30" N., 74 57' 15" E. ; 08-148 fathoms 



Stereacanthia indica, n. g. et sp. Plate V. fig. 2 ; Plate IX. fig. 19. 



This new genus is represented by two broken specimens, of which the more 

 complete, when pieced together, is about 1 1 cms. in height. 



The colony consists of two parts : (l) a long bare trunk, and (2) the branched 

 polyp-bearing portion. The trunk has a thickened basal portion in which there 

 are many projecting spieules. It is thin-walled, and consists of a number of 

 longitudinal canals with the adjacent walls fused and containing numerous large 

 spieules which help to give rigidity to the stalk. The polyp-beating portion con- 

 sists of two or three branches irregular in shape and of various lengths, with the 

 polyps closely disposed. The general colour of the polyparium is a light brown, 

 while the long trunk is white, slightly brownish at the base. 



The trunk is composed of about 20 canals with thin walls fused together and 

 filled with spieules. Owing to the contraction of the preserved specimens and the 

 thinness of the partition walls the stalk or trunk is greatly shrivelled and somewhat. 

 broken, and thus the mode of growth is not at all clear ; but it seems that the 

 polyp cavities are continued down and come into connection with the canals in the 

 branches, which are either new interstitial growths or prolongations of the can;d> 

 of the trunk. 



The trunk is divided into two irregular branches, which again divide into a 

 number of smaller branchlets or lobes, thus giving the polyp-bearing part the 

 appearance of a rugged irregular bush. The branches are unequal in size, and in 

 one specimen the thicker of the two main branches divides almost at its origin 

 into two principal parts. 



The polyps occur both on the primary branches and on the secondary branch- 

 lets or lobes. On the main branches they are scarce and arise singly, scattered 

 over the whole surface, but usually leaving a bare strip on the outer surface of the 

 branch. On the branchlets they are numerous and crowded. 



The polyps are arranged either singly or in small groups of about seven, and 

 are borne on stalks about 2 mm. in length, the basal portions of which may be 

 in close contact. They stand at an angle to the stalks. On the polyp stalks the 

 spieules are arranged obliquely transverse, except that on the dorsal side several 



