50 MISS ISA L. HILES OK GOEGONACEAN [Jan. 17, 



slenderness of stem and branches, tlie smaller size of the spicules, 

 and the fact that they are much less warted. 



It differs from M. umbraticoides Studer ^ in the absence of the 

 " halbseitig warzig " character of the spicules. 



It differs from M. complanata Wright & Studer (7) in its much 

 more slender appearance, the thinness of the ccenenchyma, and the 

 comparatively smooth character of the spindles, and also in colour 

 being white, not rose-colour. 



It differs from M. perramosa Eiclley (5) in colour and in the 

 absence of a divergent bend of the stem at the origin o£ the 

 branches. 



It differs from M. nitida Verrill (4) in colour, in the size of the 

 spicules, and the lateral position of the polyps. 



It differs from M. gracilis Wright & Studer (7) in the lateral 

 arrangement of the polyps at the ends of the branches, in the 

 much less warted spindles, and in the colour of the ccenenchyma, 

 which is not red but white. 



It differs from M. crassa Wright & Studer (7) in the thinness of 

 the ccenenchyma, the lateral arrangement of the polyps, the slender 

 character of the stem and branches, and in the much smoother 

 character of the spicules. 



MuEiCELLA TENE"BA Eiclley. (Plate III. figs. 3, 4.) 

 There is one colony ; it is 115 mm. high by 55 mm. across the 

 widest part. The main stem is 2 mm. in diameter at the base. 

 It is ramified in one plane, giving off branches on two sides at 

 angles of about 45° ; these again bear branches at angles of 

 45^-60=. 



The calyces are small and inconspicuous, -5 mm. high and 1 mm. 

 in diameter at the base. They are borne on the tAVO sides of the 

 stem and branches about 2 mm. apart. 



The branches end in two laterally placed polyps, making the 

 termination triangular in shape. 



The ccenenchyma is thin and whitish in colour ; the brown axis 

 shows through, making the whole appear fawn-colour. The polyps 

 are brown. 



The spicules are long, wavy spindles, covered with warts, which 

 are more prominent on one side than the other. They are 

 4-34 mm. X "29 mm., 2-34 mm. x -22 mm., -29 mm. x '036 mm. 



Hah. Outer slope of the reef. Depth 40-71 fathoms. This 

 specimen differs slightly from Miiricella tenera as described by 

 Ridley (5), but the differences are not very important. The calyces 

 are smaller, and the spicules are from tAvo to four times the size 

 of those of Ridley's form. 



The spicules of the calyx also are not arranged in such a regular 

 row as Ridley figures ; Wright and Studer (7. p. 124) say the 

 same about these spicules in the forms examined by them. 



Otherwise the colony decidedly approaches M. tenera : I have 



^ Studer, Th., Monatsber. d. k. Akad. d. Wiss. Berlin, 1878. 



