172 MADEEPOBAEIA. 



185. Madrepora exilis. (Plate X. figs. C, D.) 



Madrepora eanlig. Brook, Ann. Mag. N. H. 1892, vol. x. p. 457. 



CoraUum very variable in fornij shrubby arborescent to virgate with short peripheral 

 branchlets, in the latter case closely resembling some specimens of M. affinis in habit; 

 others recall the habit of M. rousseaui. In virgate specimens the branches are about 25 cm. 

 long and 1*3 cm. thick, not including the branchlets, which vary considerably in length in 

 difterent specimens. Branchlets usually 1 to 2 cm. long and 6 mm. thick, spreading almost 

 at right angles ; they are arranged all round the axis so as to give a bottle-brush appearance ; 

 apices about 1 cm. apart. In one specimen the branchlets near the apex are elongate, but 

 most of those below are short, unequal, and tapering. Axial corallites scarcely 2 mm. 

 diameter, 1'5 mm. exsert, subcylindrical, with a well-developed star of 12 septa, the directives 

 rather broader than the others. Radial corallites nariform or tubo-nariform, a little spreading, 

 becoming tubular if proliferous, usually 2 mm. long and 1'5 mm. diameter, wall firm and a 

 little thickened J the star consists of 6 moderately developed septa, the directives rather 

 broader than the others. Between the branchlets the corallites are rarely immersed; the 

 majority have a free ring-shaped border, and a few are nariform. In bushy specimens the 

 branches are shorter, more slender, and much divided, with proliferous corallites and short 

 twigs scattered irregularly over the surface of the subdivisions. Five specimens from the 

 same locality show a gradual transition from the virgate to the bushy form. CoraUum rather 

 dense ; surface and wall echinulate, not striate, but the echinulations may be arranged in 

 linear series. 



Pacific Ocean : Great-Barrier Reef area, China Sea, Arafura Sea. 



Or-f. Port Denison. Saville-Kent Coll. 92. 6. 8. 102 to 106 & 



310. (Types.) 

 ff-i. Macclesfield Bank, 13 faths. H.M.S, ' Penguin.^ 92. 10. 17. 81 to 83. 



J. Evans Bank, Arafura Sea, 10 faths. H.M.S. 'Penguin.' 92. 4. 5. 6. 



?k. SeycheUes. H.M.S. 'Alert.' 82. 10. 17. 170. 



186. Madrepora elseyi. (Plate XI. figs. E, F.) 



Madrepora elseyi, Brook, Ann. Mag. N. H. 1892, vol. x. p. 456. 



CoraUum cespito-arborescent ; branches sometimes relatively long with a cluster of 

 branchlets near the apex, at others short and much divided, resembling M. brevicollis in 

 habit. Branches 1 to 1*5 cm. diameter; branchlets and proliferous corallites very numerous 

 and usually acuminate. Axial corallites 2 to 3 mm. diameter, sometimes short cylindrical 

 with a plane margin, more usually a little tapering. Radial corallites ascending tubular, 

 rather crowded, wall thick, margin much rounded (excepting in young corallites), inner part 

 of the wall shorter than the outer and often not quite so thick ; length 2 to 4 mm. (average 

 2"5 mm.), diameter 1*5 to 2 mm. ; becoming verruciform and finally subimmersed near the 

 base ; those near the apex are relatively elongate and slender ; many proliferous corallites 



