•254 A. E, Verritt — Corals of the Genus Acropora. 



Fiji Is., U. S. Expl. Exped., No. 2007. 



This is not identical with A. armata, as supposed by Brook. See 

 remarks under the latter, above. 



It is closely allied to A. surculosa and A. cytherea, but lias much 

 smaller corallites and calicles than either of those species, and differs 

 in other ways. 



In the very numerous, small and slender upright branchlets this 

 species resembles A. arcuata (Br.), to which it appears to be nearly 

 allied. 



Acropora symmetrica (Brook) Ver. 



Madrepora symmetrica Brook, p. 94, pi. xv, 1893. 



?=Madrepora eorymbosa (pars, Lam.). Restricted by Brook, p. 97. 



? = Madrepora surculosa Dana, var. , p. 445. 



Plate XXXVI. Figure 8. Plate XXXVI A. Figure 8. 



A large specimen from Zanzibar, in the Yale Mas., seems to agree 

 closely with Brook's type, as described and figured, but is rather 

 more proliferous beneath and has somewhat longer upright superior 

 branchlets. 



Our specimen is a broad, flat-topped corymbose coral, with a 

 stout pedicel, nearer to one side. It measures about 16x18 inches, or 

 400x450 mm , across the top. 



The free part of the disk, beneath, on the widest side, is 12 inches, 

 or 300 mm . Diameter of pedicel, 3.5 inches, or 88 mm . The disk is 

 composed of intricately coalesced branches, with numerous rounded 

 openings, l_!-:30 mm or more in diameter. The under side is covered 

 with an abundance of short, irregular branchlets, more or less 

 appressed toward the margins, giving it a rough appearance. They 

 spread nearly at right angles on and near the pedicel, and are cov- 

 ered like the ccenenchyma with large immersed calicles and others 

 that are short and appressed. 



The upper side is thickly covered with rather slender, acute, fur- 

 cate and proliferous branches, upright in the middle and curved out- 

 ward and upward toward the margins, so as to rise to about one 

 general level. Many of them are 70 to 80 mm long, with the branchlets 

 mostly 25 to 50 mm long, and mostly about 6 to S mm in diameter, but 

 often with shorter distal ones, 5-10 mm long. They ai-e mostly sep- 

 arated by spaces of 10 to 20™ m at tips. 



The axial corallites are slender, about L.3 to 1.5 mm in diameter, and 

 1 to 3 mm exsert. They have a rather thin but firm, costulate wall ; 

 septa usually only six, and all narrow. 



