<^68i'4 " THETIS " SCIENTIFIC RESULTS. 



the calyx scales ia millimetres: — -544 x -442; -408 x 595; 

 •289 X -425; -272 x -306 ; -204 x -374 ; -357 x -374. The 

 eight opercular scales are of equal size — -425 x •238 mm.; 

 •391 X •204 mm. They are high, sharply-pointed isosceles 

 triangles, bearing a strong median ridge; another ridge runs at 

 right angles to the median ridge across the basal portion, so that 

 the two together form a sort of T-square. Numerous small warts 

 and jagged projections are grouped along the sides of the main 

 ridges, and occur more sparsely over the " blade " of the scale ; 

 the margins of the two long sides of the scale are entire. The 

 spicules of the ccenenchyma are for the most part scales, thicker 

 than those of the calyces, and without the clear border ; they 

 show a diversity of form, oval, fan-shaped, triangular, etc., and 

 are closely covered with tuberculate warts which surround an 

 excentric nucleus; their dimensions are: — '374 x •SQl ram.; "323 x 

 - -153 mm.; -272 x -204 mm.; -204 x ^17 mm. There are also a few 

 small approximately spherical bodies, covered with warts, '068 x 

 •068 mm.; -085 x •085 mm.; ^102 x •102 mm. 



The colour of the colonies is light brown with polyps^ of a lighter 

 shade. The axis is dark brown to greenish-bronze, and is finely 

 grooved. 



This species agrees in many respects with Pluinarella spinosa, 

 Kiikenthal. P. spinosa, however, has the opei'cular scales of 

 very Ainequal size, and the scales have throughout a rather 

 different type of ornamentation from that in our specimens. 



Locality. — Eleven miles E. by N. of Broken Bay, 30-40 

 fathoms. 



PLUMARELLA CORRUSCANS, sp. nov. 



(Plat« Ixv.,, fig. 4; pi. Ixviii., fig. 8; pi. Ixxvii.) 



Stations 40, 44, 47. 



This is an extremely beautiful and graceful form with typically 

 ieather-like branching. It is well represented both among the 

 dried specimens and among those in spirit. The largest specimen 

 is an almost perfect colony, about 44 cm. high, with a maximum 

 breadth across the branched portion of 26 cm. A well-develo])ed 

 calcareous expansion, about 2 mm. thick, attaches the colony to 

 the substratum. From this there rises a cylindrical stem, 6 mm. 

 -in diameter, which almost from its origin gives off twigs in a 

 single row along each side. At a height of about 19 cm. the stem 

 divides into two main branches, which in their turn give off lesser 



