170 MADEEPOEARIA. 



at an angle of 80° to 90°, and varying in importance from thickened and elongate proliferous 

 corallites to subterete and tapering twigs 4 cm. long and 1 cm. thick. Axial corallites 1"5 

 to 2 mm. diameter and 0*5 to 2 mm. exsert, wall thick or comparatively thin. Radial coral- 

 lites compressed nariform or tubo-nariform, unequal, the longer ones becoming tubular and 

 proliferous. Some distance below the apex all become verruciform with a dilated wall, which 

 gradually becomes reduced to a ring-shaped fold. Immersed corallites are usually wanting 

 even in the older parts of the colony, but in one or two specimens, which agree closely in 

 other respects, immersed corallites may take the place of those with a ring-shaped lip. 

 Radial corallites 1*5 mm. diameter or under, and 1'5 to 3 mm. or more in length; aperture 

 oval, wall varying in thickness in different specimens ; always thickened some distance below 

 the apex of a branch, and in some cases quite to the apex ; in the latter case the wall of the 

 axial corallites is also thickened. The axial corallites are provided with 12 septa, none of 

 which are very prominent ; those of the radial corallites are also usually narrow, including the 

 directives ; in the corallites situated some distance from the apex the second cycle is almost 

 as well developed as the first. Corallum dense, even near the apex of a branch in most 

 specimens ; surface and wall finely and closely echinulate. 



The species which Dana referred to M. abrotanoides is quite distinct from the type of 

 Lamarck, with which the description given by M. -Edwards agrees closely. The description 

 and figure of Dana agree very well with the species here described and I have therefore placed 

 the name as a synonym. It is possible that more recent authors may have taken Dana's 

 species for the true M. abrotanoides, and the synonymy is thus uncertain at present. 



There is considerable variation in this species, both in the branching and in the thickness 

 of the corallite-wall. The specimens which have come under my notice fall more or less 

 completely into three groups : — 



a. Branches elongate ; corallite-wall thin or only slightly thickened near the apex of a 



branch, but becoming considerably thickened below. A few immersed corallites may 

 or may not occur near the base of the branches. 



b. Branches shorter and more subdivided; corallites often 2*5 mm. diameter, all with 



thick wall and rounded lip. No immersed corallites. 



c. Branches thick and stunted, with short branchlets. Immersed corallites extending 



between the bases of the branchlets to near the apex. 



Indo-Pacific Ocean : Malacca, ? Fiji. 



a-e. Malacca. Capt. Belcher, R.N. [P.] . 42. 11 . 28. 1, 5 & 6 ; 42. 11. 30. 20 & 25. " 



/, g. ? ? 40. 5. 15. 23 ; 41. 2. 23, 30. 



h, i. •? ? 93. 4. 7. 158 & 159. 





183. Madrepora forskali. 



Heteropora forsJcalii, Ehrenberg, Corallenth. d. roth. Meeres, p. 113 (part.). 



Madrepora fortkalii, Dana, Zoophytes, p. 489 ; M.-Edwards & Haime, CoraUiaires, t. iii. p. 150 ; 

 Klunzinger, Korallenth. d. roth. Meeres, Th. ii. p. 17, pi. iii. fig. 6, pi. v. fig. 2, pi. ix. fig. 13. 



Corallum forming dense and much-branched clumps 10 to 20 cm. high and 15 to 20 cm. 



