166 MADREPORARIA. 
of 1 to 1:5 em.; these consist of a stout, elongate, axial corallite, provided with nariform buds, 
excepting on the inner aspect, which is nearly always devoid of corallites, excepting on the 
distal part of the more elongate branches. Immersed corallites are chiefly confined to the 
basal parts, and are usually small (0°7 mm.). Star imperfect, usually only the directive septa 
are recognizable. Corallum porous near the surface, but dense within ; surface strongly and 
closely echinulate ; wall echinulate, the echinulations are often arranged in longitudinal rows 
near the base of the cylindrical corallites situated near the apex, but not in other situations. 
Pacific Ocean: Great-Barrier Reef. 
a. Green Island. Saville-Kent Coll. 92. 6. 8. 219. \ types. 
b-d. Rocky Island. Saville-Kent Coll. 92, 6. 8. 221 to 228. 
e. Rocky Island. Saville-Kent Coll. 92.6. 8. 224. (Var.) 
jf. Capricorn Islands. Saville-Kent Coll. 92. 6. 8. 234. (Subcespitose.) 
B. Corallum forming a subcomplanate reticulum, with short twigs on the upper surface. 
177. Madrepora cancellata. (Plate XXXII. fig. C.) 
Corallum prostrate and reticulate ; branches about 1 cm. diameter, with postero-lateral 
conical corallites, which may form twigs 1:5 em. long and 5 mm. thick. The only other 
corallites on the under surface of the reticulum are immersed or subimmersed, quite distant 
and scattered. On the upper surface of the branches the corallites are mostly broad-nari- 
form, with the wall often much thickened and the margin rounded; length 2 to 3 mm., 
diameter 2 to 2°5 mm. At irregular intervals certain corallites become tubular and proliferous, 
and may then form arched twigs of variable length up to 2cm. Axial corallites conical, 
surrounded by scarcely prominent radial corallites with wide aperture ; diameter 3 mm., and 
2 mm. exsert; star well developed, the directive septa usually broadest. In the radial 
corallites the directives are very broad and stout, but all the other septa (usually 10) are quite 
narrow. Corallum very dense; surface and corallite-wall very closely echinulate. 
Louisiade Archipelago. 
a, Coralhayen, Louisiade Archipelago, 15 fathoms. 51. 9. 29. 39. (Type.) 
178. Madrepora pumila. 
Madrepora pumila, Verrill, Comm. Essex Inst. 1866, vol. v. p. 23. 
** Corallum low and spreading horizontally near the bottom, the branches spreading from 
one side of the coral. These are openly reticulated, occasionally coalescent, crooked and 
irregular, flattened from above, giving off from the sides aud upper surface short, irregular, 
scattered branchlets, many of them consisting only of a terminal cell, with one or two small 
