H)8 THE VOYAGE OF H.M.S. CHALLENGER. 



Dendrophyllia. 



Dendrophyllia cornigera, Blainville. 



Light and delicate specimens only were obtained. A single fragmentary Specimen 

 was dredged together with Corallium rubrum. 



Off St Jago, Cape Verde Islands, in 100 to 220 fathoms. 



A considerable quantity was obtained at 



Station 190, in the Arafura Sea. Lat. 8° 56' S., long. 136° 5' E. 49 fathoms. 



Stepha nophyllia, Michelin. 



Stephanophyllia complicata, Moseley (PL IV. fig. 12 ; PL XIII. figs. 3-5). 

 Stephanophyllia complicata, Moseley, Proa- Eoy. Soc, 1876, p. 558. 



The corallum is circular, free, and without trace of adherence. ; it has the form of a 

 biconvex lens, the base being very slightly curved, and the upper surface greatly so. 

 The under surface, or wall, is perforated by rows of oblong holes arranged in regular 

 series along the interspaces between the costse. The costse are fine ridges covered with 

 small swellings and granules, which radiate out with great regularity from the centre of 

 the basal disk ; they commence in the centre from six very short roots of origin, which 

 immediately bifurcate, thus becoming twelve. The bifurcation of each of the costal 

 ridges proceeds at successive distances from the centre, until at the margin of the adult 

 coral there are ninty-six costee present, sixteen in each system. The costa? at the margin 

 of the calicle are slightly grooved, showing a tendency to divide again. The perforations 

 between the costal form about twenty-two concentrically-arranged rows. The coral is 

 very convex above the septal meshwork, rising in an even curve which culminates at the 

 columella. There is scarcely any central fossa. There are six systems of septa and five 

 cycles. The primary septa are thin straight lamellae with untoothed margins, which 

 proceed directly from the periphery to the base of the columella. At . about half their 

 length from the periphery to the centre of the calicle is a notch followed by a sudden 

 rise, which forms thus a distinct palus, from the summit of which the line of the inferior 

 margin of the septum slopes sharply down to the base of the columella. The secondary 

 septa are also straight thin lamina? ; they can be traced in the adult coral no further than 

 for about one-third the distance from the periphery to the columella, since they are here 

 covered by the tertiary septa, which, bending over the secondary septa at this point, 

 bring together their upper margins, and, fusing with one another, form stout laminae, 

 which run in a radial direction to join the columella, and are the stoutest and most con- 

 spicuous septa in the coral. From their point of junction with the secondary septa, the 

 tertiary septa curve outwards towards the primary septa on either side in each system ; 

 and each of them being joined on its side next the primary septa by a curved quaternary 



