6 SYDNEY J. HICKSON. 



at the nodes and • 6 mm. at the internodes. The ramification is irregular and in all 

 directions, but the branches in all cases arise at an acute angle from the calcareous 

 internodes. The coenenchym is very thin, and is absent from a great many of the 

 branches. The terminal branches are about " 3 mm. in diameter at the base, and 

 attenuate distally to a very fine point. 



The internodes are 6 mm. long. Here and there shorter internodes occur, but 

 on the whole the length of the internodes is fairly constant. The calices are quite 

 irregularly scattered. Usually a group of four or five calices situated at intervals of 

 1 or 2 mm. stands apart from other groups, but as a great many calices have dropped 

 off, this grouping may be the result of injury. 



The calices are bent at an acute angle to the axis ; the outside measurement is 

 about ■ 65 mm. The diameter of the calyx at the base is • 3 mm., and at the crown 

 0*4 mm. The spicules of the coenenchym are flat, tuberculated spindles, varying 

 from 0*2 mm. to O'l mm. in length (fig. 12a). On the neck of the calyx similar 

 spicules, somewhat bent, are arranged in fourteen or fifteen horizontal rows. The 

 spicules of the crown and of the backs of the tentacles are often expanded at one end 

 to form a triangle (fig. 12b). 



CeRATOISIS (PbIMNOISIS) ANTARCTICA. 



(Plate II., figs. 13, 14, 15.) 

 Isis antarcUca, Studer, MB. Ak. Berlin 1878, p. 662. 



Locality :— (l) McMurdo Bay, February 8, 1902, 96-120 fathoms^; (2) McMurdo 

 Bay, February 28, 1902, 20 fathoms. 



The two specimens which may be attributed to this species are broken from their 

 base, and each measures about 50 mm. in height. It is probable that they were torn 

 from the same colony. The branching is quite irregular and shrubby. The internodes 

 are about 6 mm. in length, but vary a good deal more than in C. delicatula. The 

 thickest internode in the specimen is about 0*9 mm. in diameter. The calices are 

 numerous, and situated at intervals of about 2 or 3 mm. on the branches, but gathered 

 close together in clusters near the extremities. I cannot recognise any spiral arrange- 

 ment of the calices such as that described for the type by Professors Wright and Studer 

 (14). Each full-grown calyx is from 1 to 1 • 5 mm. in height and stands out almost at 

 right angles to the axis. 



The spicules of the coenenchym are flat spindles about 0'3 mm. in length (fig. 14a), 

 and those at the base of the calices are bent. The calices are protected by overlapping 

 scales of very irregular form and size, but usually straight on one side, convex on the 

 other, and not exceeding 0"3 mm. in length (fig. 14b). The scales on the back of the 

 tentacles are all horizontally placed (fig. 15). 



The type of this species was obtained by the ' Gazelle ' in 60 fathoms ofi" 

 Kerguelen (Studer (10), p. 661), and subsequently specimens were obtained by the 

 'Challenger' in 310 fathoms off" Prince Edward Island. I have compared the 



