118 MADREPORARIA. 
3 mm. diameter, not over 2 mm. long, and usually less. The aperture is very wide and the 
septa very prominent. Wall closely striate. 
Indo-Pacific Ocean: Ceylon, Singapore, Great-Barrier Reef area. 
a-o. Cleremont Island. Saville-Kent Coll. 92. 6. 8. 165 to 178 & 186. 
p. Port Denison. Saville-Kent Coll. 92. 6. 8.179. 
?q. Low Woody Island. Saville-Kent Coll. 92. 6. 8. 180. 
?r-t. Rocky Island. Saville-Kent Coll. 92. 6. 8. 181, 183 & 184. 
u. Thursday Island. Saville-Kent Coll. 92. 6. 8. 182. 
v. Green Island. Saville-Kent Coll. 92. 6. 8. 266. 
w. Rocky Island. Sayille-Kent Coll. 92. 6. 8. 267. 
a. Rocky Island. Saville-Kent Coll. 92. 6. 8. 268. 
y. Ceylon. Haeckel Coll. 92. 12. 5. 30. 
Var. compacta. 
a-g. Rocky Island. Saville-Kent Coll. 92. 6. 8. 128 to 134. 
h. Cleremont Island. Saville-Kent Coll. 92.6. 8. 185. 
i-l, Capricorn Islands. Saville-Kent Coll. 92. 6. 8. 190 to 192 & 263. 
115. Madrepora convexa. 
Madrepora convexa, Dana, Zoophytes, p. 449 ; M.-Edwards & Haime, Coralliaires, t. iii. p. 158; Verrill, 
Bull. Mus. Comp. Zool. 1864, vol. i. p. 42; Studer, MB. Mitth. naturf. Ges. Bern, 1880, p. 20; 
Rathbun, Proc. U.S. Nat. Mus. 1887, vol. x. p. 15; Ortmann, Zool. JB. 1888, Bd. iii. p. 153; 
ibid. 1889, Bd. iv. p. 508 (part.). 
? Madrepora corymbosa, Verrill (non Dana), Bull. Mus. Comp. Zool. 1864, vol. i. p, 42. 
Corallum low corymbose, upper surface flattened or convex, 25 cm. or more in diameter. 
Main branches nearly horizontal, complanate below, reticulato-coalescent, with a few short, 
naked and subangular branchlets in the general plane. Corallites on the under surface all 
immersed or subimmersed excepting at the margin of the colony, or in some specimens with 
a few scattered, thick, bursiform or appressed tubular ones. Branchlets on the upper surface 
simple or subsimple and terete near the centre of the colony, more divided or proliferous near 
the margin, 5 to 7 mm. thick and 2°5 to 6 cm. long, varying in different specimens, mostly 
tapermg, apex not very obtuse. Axial corallites short, cylindrical, 1 to 2 mm. thick and 
1 mm. exsert, wall very porous and a little thickened. Radial corallites equal, scale-like or 
labellate, crowded, and spreading almost at right angles, with a broad or rather narrow flat- 
tened fragile lip, 15 mm. long and 1 to 2 mm. broad. Septa in two cycles, both well 
developed in the axial corallites; in the radial ones the second cycle is rudimentary but 
rarely absent. Coenenchyma very porous; wall delicate, striato-echinulate. 
A cespitose specimen 18 cm. in diameter, from Tongatabu, differs only in habit and in 
the more proliferous branchlets and slightly unequal corallites. 
This species is distinguished from M. millepora by the shorter, more simple, and tapering 
