194 MADEEPOEAEIA. 



together than is usually the case. Corallum very dense ; surface subrugose and very finely 

 echinulate ; wall striate and finely echinulate. 



China Sea. 



} Types. 



a. Macclesfield Bank, 37 fath. H.M.S. ' Penguin.' 92. 10. 17. 33. 



b. Macclesfield Bank, 31 fath. H.M.S. ' Penguin.' 92. 10. 17. 34. 



210. Madrepora inermis. (Plate XXIX. figs. A, B.) 

 Madrepora inermis. Brook, Ann. Mag. N. H. 1891, vol. viii. p. 462. 



Corallum consisting of slender laxly-divided branches, which probably extend subhori- 

 zontally. The branches are about 21 cm. long and 8 mm. thick, somewhat flattened in places 

 and completely or almost completely devoid of corallites on the under surface, forked and 

 divaricately branched; the branchlets are sublateral, 1'5 to 6 cm. long, 4 to 5 mm. thick, 

 scarcely tapering, those under 5 cm. in length are usually simple. In addition to the more 

 noticeable branchlets, there are a few short, lateral, subalternate ramiculi on the stouter 

 branchlets at intervals of about 1 cm., they are 4 to 8 mm. long and 3 mm. thick. Axial 

 corallites 2 mm. diameter, 1 mm. exsert, wall scarcely thickened, with a star of 6 well-deve- 

 loped septa and sometimes traces of a second cycle. Radial corallites very short, spreading 

 tubular, rather distant, often with indications of a subspiral arrangement ; length 1 to 2 mm. ; 

 diameter the same, but usually 1'5 mm., and the base may be dilated; those near the apex of 

 a branchlet are not so spreading, but the aperture is always rounded ; the longest ones are 

 lateral in position and, on becoming proliferous, give rise to the short ramiculi already referred 

 to. Immersed corallites are practically absent. Wall thin but firm ; the septa are arranged 

 in a single cycle, the lower directive often mucli broader than the others. Corallum very 

 dense ; surface dense, smooth on the underside, slightly rough but not spinose on the anterior 

 surface of the stouter branches. The wall of the axial and younger radial corallites is roughly 

 costulate and the striations are continued to the coenenchyma, but below the striations are 

 lost on the corallites as well as on the general surface. 



South Seas, 

 a, 6. South Seas. Purchased. 41. 12. 11.6 & 7. (Types.) 



211. Madrepora parills. 

 Madrepora parilis, Quelch, ' Challenger ' Reef Corals, p. 162, pi. ix. fig. 3. 



Corallum spreading more or less horizontally, the branches and branchlets developing 

 continuously in one plane from opposite sides of the larger branches, and nearly of equal size 

 throughout, viz. 5 to 7 mm. thick. Branches round or vertically compressed, closely placed, 

 rarely coalescent, although extending nearly at right angles. Axial corallites cylindrical, 2 to 

 3 mm. diameter, with moderately thick and porous wall, not rounded at the margin ; the star 

 consists of 12 septa, the directives broadest. The radial corallites are wide apart, tubular, 



