334 DISCOVERY REPORTS 



identifications are correct, and, as far as they are described, to various fossil species of 

 Vaughan and others. M. kauaiensis Vaughan has lo smaller septa of a second cycle, 

 not reaching the columella. The cyclical number of ten is most important, the newly 

 formed calices having no intervening stage with six septa so far as can be seen from an 

 examination of budding. 



The genus varies in growth-form from fine branches to upstanding nodules or branches 

 on a completely incrusting base. The latter may show no such upgrowths and may 

 reach a considerable thickness so that the coral would be termed massive. Finally, in 

 the lower parts of colonies the calices may be separated relatively widely by coenen- 

 chyma, this studded with low spines. The calices vary up to 3 mm. diameter. They may 

 be divided by a thin sharp-edged upstanding theca or this may be quite thick and 

 rounded, the whole perhaps flattened so as to give a depressed appearance. The presence 

 of low, projecting rods around the top of the theca is usually a specific character, but 

 an appearance of a few such may occur in any species. 



The genus, as defined above, does not allow the retention of Madracis scotiae which 

 I described in the account of the corals of the Scottish Antarctic Expedition in 1913; 

 this has 8 septa, but definitely passes through a six stage. Probably it should be referred 

 to Axhelia Ed. and H. 



Madracis decactis (Lym.) Ver. 



Pourtales, ///. Cat. Mus. Comp. Zool. Harvard, iv, 67, VII 1-3 (1871); Verrill, Zool. Bermudas, 

 I, 108 (1903). 



A single mass with irregular surface 6 by 4-5 cm. and 4-5 cm. high from St. 283, near 

 Annobon Island, is referred here. Below its surface for 4 to 6 mm. the corallum is 

 intact ; this sits upon several layers of skeleton much decayed owing to the action of 

 boring organisms. The calices are seldom more than 2 mm. in diameter; they may be 

 crowded together and smaller where growth is active, these having thin, thecal walls. 

 In hollows the calicular centres are somewhat separated, the theca greatly thickened, 

 generally marked on the surface by a single row of blunt spines. Budding occurs on the 

 edge and on actively growing knobs where three caHces meet ; in these it is very rare to 

 find less than 10 septa if the theca is perfect. The columella is always present, but it is 

 seldom surrounded by a circle of paliform-teeth. 



The species described by Rehberg {Abh. Nat. Ver., Hamburg, xii, 10, I 3, 4, 1892) 

 as M. singularis seems to fall within the range of decactis; it was obtained at 80 fm., at 

 Fiji. Some calices in the present specimen are identical with those figured by Rehberg. 



Genus Dendrophyllia (Blainville), Ed. and H. 

 Dendrophyllia oahensis Vaughan. 



Bull. U.S. Nat. Mus. no. 59, p. 154, XLVI i (1907). 

 St. WS 244, 253-247 m. 



Seven small colonies are here assigned, largely on the faith of Vaughan's photographs, 

 of which one shows the costae and another brings out the very characteristic kind of 

 network fusion together of the septa to form a thick wall. All have a semi-upright 



