MADREPORA. 173 © 
occur at intervals, some of which form twigs, others remain short and nipple-shaped ; 
sometimes quite half the corallites on one surface of a branch bear buds, at others very few. 
Star well developed, the two directive septa very broad. Corallum dense; surface and wall 
densely echinulate, not striate, though striato-echinulate when thin, 
Pacific Ocean: Torres Straits and Great-Barrier Reef area. 
a-g. North Australia. J. R. Elsey, Esq. [P.]. 57. 11. 18. 204, 209, 214 
to 218. (Types.) 
h-l. Thursday Island. Saville-Kent Coll. 92. 6. 8. 241-245 
m. North Australia. Saville-Kent Coll. 92. 6. 8. 246. 
n. Rocky Island. Saville-Kent Coll. 92. 6. 8. 247. 
8. Subgenus RHABDOCYATHUS. 
Axial corallites stout, cylindrical, the free portion not usually longer than broad ; wall 
thick and dense; margin more or less rounded ; star usually 12-rayed. The more prominent 
radial corallites are also thick-walled and are usually provided with more than six septa; 
they sometimes also resemble the axial ones inform. The habit is either bushy, fruticose, or 
flattened and reticulate, with branchlets on the upper surface only. There is sometimes an 
approach to the bottle-brush form in the arrangement of the twigs, but in such cases, so far 
as known, the twigs are always longer on one side of a branch than on the other. 
A. Corallum bushy, fruticose or subarborescent. Radial corallites of the same form as the 
axial ones, and some of them are scarcely smaller in diameter. 
187. Madrepora hemprichi. 
Heteropora hemprichit, Ehrenberg, Corallenth. d. roth. Meeres, p. 109. 
Madrepora forskali (part.), M.-Edwards & Haime (non Ehrenberg), Coralliaires, t. 111. p. 151. 
Madrepora hemprichii, Klunzinger, Korallenth. d. roth. Meeres, Th. ii. p. 6, pl. i. fig. 2, pl. iv. fig. 17, 
pl. ix. fig. 1; Ortmann, Zool. JB, 1888, Bd. iii. p. 149; ibid. 1889, Bd. iv. p. 503 (non 
Haeckel, Arab. Korallen, pl. ii. fig. 6). 
Madrepora obtusata, Klunzinger, Korallenth. d. roth. Meeres, Th. ii. p. 7, pl. i. fig. 5, pl. iv. fig. 18, 
pl. viii. fig. 20, pl. ix. fig. 2; Ortmann, Zool. JB. 1888, Bd. iii. p. 149. 
Madrepora variolosa, Klunzinger, Korallenth. d. roth. Meeres, Th. ii. p. 8, pl. i. fig. 6, pl. iv. fig. 16, 
pl. ix. fig. 3. 
? Madrepora rudis, Rehberg, Abhand. nat. Ver. Hamburg, 1892, Bad. xii. p. 41, pl. iv. fig. 9. 
Corallum laxly arborescent or bushy, erect or oblique, with or without occasional 
fusions, 15 to 20 cm. high, or more in the case of slender arborescent forms. Branches 
usually about 1 em. thick, sometimes elongate and little divided, at others shorter and much 
branched, tapering somewhat towards the apex. Axial corallites 4 to 5 mm. broad, 3 to 
2A 
