MADREPORA. 25 
Rey. d. Zooph. d. Antilles, p. 32; Pourtalés, Ilustr. Cat. Mus. Comp. Zool. pt. iv. p. 84; 
L. Agassiz, Mem. Mus. Comp. Zool. 1880, vol. vii. pl. xviii.; Quelch, ‘Challenger’ Reef Corals, 
p- 149; Rathbun, Proc. U.S. Nat. Mus. 1887, vol. x. p. 13. 
Heteropora regalis, Ehrenberg, Corallenth. d. roth. Meeres, p. 111. 
Madrepora regalis, M.-Edwards & Haime, Coralliaires, t. iii. p. 139. 
Heteropora laxa, Ehrenberg (non Lamarck), Corallenth. d. roth. Meeres, p. 110. 
Madrepora superba, Klunzinger, Korallth. d. roth. Meeres, Th. ii. pp. 19, 20, pl. iii. fig. 1, pl. iv. fig. 5, 
pl. ix. fig. 15; Mobius, Beitr. z. Meeresfauna Mauritius, p. 45; Faurot, Arch. Zool. expér. 1888, 
tanvisepaplalos 
Madrepora secunda, Ortmann, Zool. JB. 1888, Bd. iui. p. 150 (part.). 
A. Forma palmata. 
Corallum frequently flabellate or palmate ; fronds large, thin, and usually solid quite to 
the margin, flat or curved, often several radiating from an incrusting base. Some specimens 
are short, stout, vasiform, with a thick pedicel and broad base, branches quite indistin- 
guishable. The flabellate forms consist of fronds often 60 cm. long and 40 cm. or more 
broad, forming solid plates about 8 mm. thick at the apex and 1 to 2m. near the base. The 
fronds may be entire or divided by narrow fissures into lobes. In other cases they are 
alciform (M. alees, Dana), with the branches composing each lobe confluent quite to the 
apex. In the majority of specimens the branches are only recognizable near the margin of 
the corallum, but in some their course is indicated by furrows on the surface. Axial 
corallites sometimes scarcely recognizable, particularly in vasiform specimens. In other 
cases the marginal divisions of the branches bear axial corallites 2 to 2°5 or even 3 mm. 
diameter and | to 3 mm. exsert. Wall sometimes rather thin, but usually thick and 
porous, strongly striate exteriorly; the largest corallites usually occur in branches which 
are comparatively free near the apex. Radial corallites prominent on both sides of the 
frond or only on the upper one. Prominent radial corallites tubular, with a more or less 
oblique aperture; sometimes half-tubular, labellate, or nariform, often unequal in length, 
1 to 4mm. or even 5 mm., and | to 2 mm. thick, but usually between 1-5 mm. and 1:8 mm. 
They arise at an angle of about 45° on the branches, but in the flabellate portion are more 
spreading, frequently at right angles. A variabie number of immersed corallites occur 
between the others; in some specimens they are not numerous, in others quite half the 
corallites are immersed. The length, as well as the prevailing form of the prominent 
corallites, varies very much in different specimens, even from the same locality. Star 
little developed, consisting usually of slightly prominent directive septa and four others 
which are rudimentary. Corallum always porous and reticulate in section near the apex, 
but frequently dense below; surface spongy-echinulate ; wall striate and usually echinulate 
near the base; the strize are much more prominent in some specimens than in others. 
The majority of the specimens which have come under my notice do not suggest a very 
close affinity to the arborescent forms prolifera and cervicornis, and for some time I was 
inclined to regard them as distinct. Nevertheless a number of intermediate forms occur, 
chiefly in the collection of the British Museum, which appear to render it necessary to 
