MADEEPOEA. Ill 



branches 2 cm. thick, giving rise to subparallel divisions over 1"5 cm. diameter, each of which 

 bears a series of branchlets on its outer surface. Branchlets simple, bi- or trifid, arising 

 obliquely, but arched near the base so that the distal part extends vertically, length 3 to 

 4" 5 cm., diameter 7 or 8 mm. near the base, slowly tapering, apices about 1"5 cm. apart, but 

 many are divided near the apex. Axial corallites 2 mm. diameter, usually not over 1 mm. 

 exsertj wall very porous, margin plane, star very well developed. Radial corallites half- 

 tubular, labellate, or tubular with an oblique apex ; the form varies with the greater or less 

 development of the inner part of the wall; the majority arise at an angle of about 45°; 

 length on the distal parts 2 to 3" 5 mm., diameter across the lip about 2 mm. ; those situated 

 below the middle of a branchlet are short tubular, with a round aperture ; immersed coral- 

 lites do not usually occur on the branchlets, and on the main divisions they are small. The 

 branchlets on the under surface are practically identical with those above, but many are 

 only 26 cm. long, though others may be 4*5 cm. The primary septa are very well developed in 

 nearly all cases, and the directives often nearly meet in the middle line ; the second cycle may 

 also be well developed. Corallum rather porous, surface spongy echinulate ; wall thin and 

 fenestrated at first, with increase in thickness the striae become replaced by echinulations in 

 longitudinal rows, 



Java. 



a. Java. Purchased. 59. 12. 12. 2. (Type.) 



106. Madrepora patula. (Plate IX. fig. E.) 



Madrepora patula, Brook, Ann. Mag. N. H. 1892, vol. x. p. 460. 



Corallum broad, depressed, bushy from a short simple stem, hemispherical ; 29 era. broad, 

 10 cm. high. Branches radiating, 1'4 cm. diameter, dividing) two or three times in the same 

 plane. Branchlets on the upper surface erect, spiciform, simple or divided near the base into 

 two or more subparallel divisions, the distal portions of which are simple or further sub- 

 divided; length 2 to 4'5 cm., diameter at the base 6 to 7 mm. if simple, gradually tapering; 

 apices about 1'4 cm. apart. Axial corallites cylindrical, 2 mm. diameter, 2 mm. exsert; 

 wall a little thickened but very porous, margin plane. Radial corallites chiefly nariform, 

 outer part of the wall at an angle of about 45°, remaining more or less prominent quite to the 

 base of the branchlets ; a few have the outer part of the wall more elongate and labellate ; 

 length 2 mm., rarely 3 mm., diameter 1'2 to 1'5 mm. ; wall usually thin and fragile, but may 

 be a little thickened near the base of the branchlets. Immersed corallites on the upper 

 surface of the corallum distant, 1 mm. diameter. Star imperfectly develoijcd, usually only the 

 directive septa are recognizable in the prominent corallites ; but near the base of the branchlets, 

 in subimmersed cells, a second cycle of septa is usually present, and the directives may be very 

 broad. Branchlets on the under surface 8 to 16 mm. long and about 4 mm. diameter, tapering 

 to an axial corallite rarely more than 1-5 mm. exsert. Radial corallites chiefly forming sub- 

 immersed dilatations, but a few are nariform and a few which indicate new outgrowths are 



q2 



