160 THE VOYAGE OF H.M.S. CHALLENGER. 



The epitheca is marked at intervals by several horizontal folds or ridges, and in its 

 upper region is thrown into a series of longitudinal costal folds which are equally- 

 developed and only very slightly prominent. In some parts of the wall they are 

 marked on the lower part of the corallum also, being traceable nearly to the apex. 

 Towards the edge of the calicle the epitheca shows a triple margin appearing as if 

 produced by three intervals in growth. The rounded edges of the primary and 

 secondary septa can just be seen above the level of the margin of the calicle, which is 

 nearly circular in outline. The sexradiate arrangement of the septa is a little obscured 

 by irregularities, but can be plainly made out. There are six systems and four cycles, 

 with additional septa in three pairs of the systems. The additional septa are developed 

 symmetrically in pairs as regards the longer transverse axis of the calicle, but not as 

 regards the opposite ends of that axis. The septa are quite straight with smooth faces ; 

 their inner edges are straight and perpendicular and parallel to the face of the columella, 

 which they join only at a considerable depth within the calicle by curving horizontally 

 inwards just as occurs in Sphenotrochus rubescens, with which coral the present agrees 

 also in the form of the columella. At the margin of the calicle at a little distance below 

 the edge of the epithecal border, and at a short distance below their own outer summits, 

 the outer regions of all the septa are soldered together by a zone of stereoplasma (the 

 name by which Lindstrom 1 denotes the solid calcareous matter filling up the interior of 

 such corals as this and Duncania) which extends down for about one-third of the height 

 of the calicle. The lower part of the calicle is quite free from stereoplasma or other filling 

 up, but hollow to the apex, and the wall of the lower part is so thin as to be translucent 

 when held up to the light. The columella is somewhat elongate in the outline of its summit, 

 indicating thus the position of the longer transverse axis of the calicle. It is composed 

 of four vertical flattened pillars fused together below but free at their tips. It projects up 

 free within the fossa for a height of 2 mm. 



Height of the calicle, 8 mm. Diameter of the calicle, 6 mm. 



One specimen only dredged, attached to a fragment of volcanic rock. 



Station 194. Off Banda Island, East Indies. 60 fathoms. 



Desmophyllum. 



Desmophyllv/m ingens, n. sp. (PI. IV. figs. 1-6, la-ba, PI. V. figs. 1-to 4, l«-4«). 



In the fjords of Western Patagonia were dredged numerous specimens of a gigantic 

 Desmophyllum which seems closely allied to Desmophyllv/m crista galli, but which, 

 because of its extraordinary size, and because an exactly similar coral occurs in Sicilian 

 Tertiary beds, I have termed Desmophyllum ingens. Various forms of the coralla are 

 figured on Plate V. of the natural size. The coralla are extremely massive and heavj'. 

 The shapes are exceedingly various according, to some extent, to the positions in which the 



1 Actiuology of the Atlantic, p. 13. 



