186 MADEEPORAEIA. 



divisions are simple or bear one, rarely two, short appressed tubular buds. The majority are 

 1*5 mm. diameter, scarcely tapering, but the more elongate ones are thicker at the base; all 

 are usually a little over 1 mm. diameter at the apex. Margin plane, aperture not contracted; 

 the star consists of six well-developed septa, the directives being very frequently fused 

 together in the middle line ; wall rather thin but firm. Corallum dense and little porous, 

 excepting near the apex of a colony ; surface dense, pitted in parts, more or less strongly 

 echinulate ; wall striate and echinulate, becoming finely echinulate below. The condition of 

 the surface and the prominence or even the presence of striae on the wall vary considerably in 

 different parts of the same specimen. The corallites on the stem and main branches are 

 immersed, distant, 1 mm. diameter, with the directive septa usually fused together. 



I have compared the type of M. durvillei with what appear to me to be typical speci- 

 mens of M. echinata, and have been unable to recognize any constant differences which can 

 be considered of specific value. M. -Edwards's figure of M. echinata is not typical, and 

 probably should be referred to another species. As a variety, M. durvillei may be recognized 

 by the following characters : — 1. Ccenenchyma strongly striate and echinulate. 2. Star little 

 developed in the immersed corallites. 3. The aperture of tubular corallites may be slightly 

 contracted. 



Pacific Ocean : Fiji, Samoa, Australia, Sulu Sea, Sandwich Islands, Liu Kiu Islands. 



a. Australia. Sydney Museum. 84. 11. 25. 1. 



*, c. Pacific Ocean. G. Holsworth, Esq. [P.]. 91. 11. 5. 1 & 2. 



d. ? Purchased. 43. 3. 6. 129. 



200. Madrepora subglabra. (Plate XXIX. fig. C.) 



Madrepora subglabra, Brook, Ann. Mag. N, H. 1891, vol. viii. p. 470. 

 Madrepora echinata, Quelch, ru)n, Dana, ' Challenger' Reef Corals, p. 162. 



Corallum extending in elongate, slender, and oblique or subprostrate branches, closely 

 resembling M. procumbens in habit and in the form of the branchlets. Branches 6 to 18 cm. 

 long, 7 mm. diameter, not terete, owing to the swollen bases of the branchlets. Branchlets 

 1 to 4 cm. long, similar to those of M. procumbens, but the corallites are more slender, 

 scarcely over 1 mm. diameter at the apex ; margin plane, aperture not contracted ; they vary 

 from 4 to 15 mm. in length, the majority are about 7 mm. long, the terminal 3 or 4 mm. 

 being free from budding corallites. The main branches bear a very small number of sub- 

 immersed corallites about 0'7 mm. diameter. The star consists of six septa, the directives 

 being thick and prominent, the others much narrower. Corallum dense; surface almost 

 smooth, excepting near the apex, where it is finely echinulate ; wall very finely striato- 

 echinxUate at first, the striae becoming lost later, and subsequently the echinulations as well. 



The ' Challenger ' specimens referred by Quelch to M. echinata, together with another 

 specimen in the Collection, appear to differ from the above in having a slightly more prostrate 

 habit and in the presence of stronger echinulations ; but in these the echinulations are much 

 finer and shorter on the inferior surface of the branches. 



