l66 PAPERS FROM THE DEPARTMENT OF MARINE BIOLOGY. 



costules are prominent and plate-like. The edge is at first acute, but with subsequent 

 thickening it becomes obtuse or rounded. The inner wall is absent, thin, or considerably 

 developed, but the aperture remains oblique. Usually, unless the corallites are greatly 

 compressed, 2 cycles of septa are present, the primaries the more prominent, the outer 

 directive large; secondaries small, usually rudimentary. 



Ccenenchyma near the branch ends costulate, reticulate, and echinulate, subsequently 

 becomes almost solid. 



Station, Murray Island. — Southeast reef, Lithothamnion ridge, 1,725 to 1,850 

 feet from shore; from tide pools and crevices, where it was constantly swept by 

 breakers at low tide. 



Distribution. — Great Barrier Reef. 



Brook's figures of his M. decipiens are so poor that no details of the corallites, 

 only the growth-form, can be made out from them, and he does not sufficiently 

 describe the transverse outline of the corallites. However, it seems improbable 

 that the specimen I am identifying as M. decipiens could be anything else. 



Acropora (Eumadrepora) abrotanoides (Lamarck). 

 Plate 6S, figures i, la, 2, specimens from Murray Island. 

 1893. Madrepora abrotanoides Brook, Cat. Genus Madrepora, p. 56. 



I am referring three small, immature specimens, two of which are figured, to 

 this species. In general aspect they closely resemble A. decipiens, but a larger 

 number of the proliferous corallites form short twigs; the inner walls of the pro- 

 tuberant radial corallites are better developed, becoming "ultimately similar to 

 the axial ones,"' and the septa of the radial corallites are much better developed. 

 Thty zve cXos&no Acropora danai{M.EA-w. and H.) (typeinU.S. Nat. Mus.,No. 303), 

 but the radial corallites of the latter have very perforate walls, of lace-Uke structure 

 and texture, whereas in the specimens I am referring to A. abrotanoides the walls 

 are relatively compact, as in A. decipiens. 



Station, Murray Island. — Southeast reef, line I, 1,200 feet from shore; depth 

 12 to 16 inches; bottom rocky. 



Distribution. — Tahiti; Great Barrier Reef; Singapore. 



Acropora (Eumadrepora) pharaonis (Milne Edwards). 



Plate 69, figures l, 2, 3, 30, 4, 4a, 5; plate 70, figures i, 2, la, specimens from Cocos-Keeling Islands. 



i860. Madrepora pharaonis Milne Edwards, Hist. nat. Corall., vol. 3, p. 143. 

 1893. Madrepora pharaonis Brook, Cat. Genus Madrepora, p. 58. 



1906. Acropora pharaonis von Marenzeller, Denksch., k. k. Akad. Wiss. Wien, vol. 80, p. 35, plates 4-S, 



figs. 1018; plate 9, figs, \oa-ija. 



1907. Madrepora pulchra Wood Jones, Proc. Zool. Soc. London for 1907, p. 534, text-figs. 155, 156; p. 543, 



text-fig. 160; p. 544, text-fig. 161; plate 27, fig. 2a (both figures), fig. zb (left-hand figure). 

 1910. Madrepora Wood Jones, Coral and Atolls, p. 75, text-fig. 13; p. 89, text-fig. 24a (both figures), 24* 

 (left-hand figure), p. 113, text-figs. 40, 41. 



1910. Madrepora pulchra Wood Jones, Coral and Atolls, p. 96, text-figs. 29, 30. 



191 1. Madrepora pharaonis Gravier, Ann. Inst. Oceanogr., vol. 2, fasc. 3, p. 73, plate lo, figs. 42, 43. 



Brook published the following descriptions of Milne Edwards's types oi Madre- 

 pora pharaonis and M. pustulosa: 



"Type. Corallum arborescent with stout branches, between which occasional fusions 

 occur, recalling the habit of M. crassa. Branches 2.3 cm. thick, 30 cm. long, laxly sub- 

 divided. Axial corallites 2.5 mm. diameter, 1.5 mm. exsert; septa in two cycles, with 

 directives scarcely broader than the other primaries. Radial corallites chiefly immersed, 

 with a few labellate, but scattered between are tubular ones almost at right angles; about 

 5 are distributed to each 2.5 cm.; these are 3 mm. long and 2 mm. diameter, and mostly 

 bear a rosette of short labellate corallites. The tubular proliferous corallites have appar- 



'Brook, op. sup. cil. 



