REPORT ON CORALS — DEEP-SEA MADREPORARIA. 157 



Height of the coralla, 15 mm. and 22 mm. respectively. Diameters of the calicles, 

 10 mm. and 12 mm. 



Station 320, off the mouth of the Eio de la Plata. 600 fathoms. One specimen. 

 Station 163, off Twofold Bay, New South Wales. 120 fathoms. One specimen. 



Cyathoceras rubescens, n. sp. (PI. II. fig. 8, 8a, 86, 8c). 



Corallum of a very pale reddish tint, white in places, elongate conical, curved, much 

 compressed in its upper part, with a cylindrical stout pedicle terminating in an expanded 

 and encrusting base. Surface glistening but slightly roughened. Costa? more marked on 

 one face than on the other, little prominent, except just at the margin of the calicle 

 where all the exsert septa are continued a very short distance down the wall. Septa 

 all exsert, with rounded edges ; the cpiinary higher than the cpiarternary, and joined 

 for nearly their entire height externally to the adjacent primaries, secondaries, and 

 tertiaries, those next the tertiaries not so high as those next septa of higher order. 

 Calicle elliptical in outline, with a deep fossa. Septa in six systems and five cycles, one 

 pair of systems being incomplete in the only specimen. Septa free from attachment to one 

 another, straight, with smooth surfaces, and slightly sinuous inner margins. Columella 

 elongate in form, prominent in the fossa, composed of numerous more or less spirally 

 twisted thin laminae. 



Height of the corallum, 35 mm. Breadth of the calicle, 23 mm. 



One perfect specimen, only attached to a dead fragment of another. 



Station 192, off the Ki Islands. 129 fathoms. 



Sphenotrochus. 

 Sphenotrochus rubescens, Moseley (PL VI. fig. 8, 8a). 



Plat yt melius rubescens, Moseley, Proc. Roy. Soc, 1876, p. 553. 

 The corallum is of a light red colour. It is compressed and wedge-shaped, without 

 trace of adherence, and provided with lateral aliform expansions derived from the lateral 

 costae. The surface of the wall is roughened all over by the costse or their prolongations, 

 and on the alae by transverse ridges. The whole of these ridges and costae are covered 

 with minute sharp granules, so that the entire surface of the coral feels rough to the 

 touch, like fine sand-paper. The costse commence as the continuations of the borders of 

 the exsert septa, and are there prominent thin lamina?. They gradually decrease in 

 elevation towards the base, where they appear as small narrow ridges, which are some- 

 what confused and interrupted here and there, though all converging in direction towards 

 the apex of the coral cup. The primary and secondary costee are near the margin of 

 the calicle, somewhat thicker than the others, but otherwise all the costse are equally 

 developed and of an even height, except the two lateral ones, in three out of four 

 specimens procured. In the fourth specimen the primary and secondary costse are a 



