242 A. E. Verrill — Corals of the Genus Acropora. 



A fragment of the original type, from near Hong Kong, is in the 

 Yale Museum, No. 886. The rest is in the U. S. Nat. Mus. 



. I . glcrnca (Brook) is evidently closely related to this species, and 

 very likely may be identical with it. 



Acropora turbinata (Dana) Ver. 



Madrepora surculosa, var. turbinata Dana, Zooph., p. 446, pi. xxxii, fig. 5 r 



1846. Brook, op. cit., p. 200, 1893. 

 Madrepora turbinata Verrill, Bull. Mus. Comp. Zoo]., i, p. 42, 1864. 

 ? Madrepora armata Brook, 1892 ; Brook, Catal., p. 100, pi. x, figs. A. B. 



Plate XXXVI. Figure 6. Plate XXXVI A. Figure 6. 



Plate XXXVI F. Figure 2. 



The type of this form, which Dana considered a marked variety 

 of surctdosa, is in the Museum of Yale University, No. 2017. 



It appears to be a species quite distinct from Dana's type of M. 

 surculosa, from the Fiji Islands, fragments of which are also in the 

 Yale Museum, No. 4181. 



This coral forms a somewhat turbinate corymbose, nearly flat 

 clump, consisting of stout, divergent, ascending primary branches, 

 arising from an incrusting base and rarely coalescent. The exterior 

 surfaces of the outer branches, from the base up, are covered with 

 numerous, small, irregular, divergent, proliferous branches, not at all 

 appressed, which give the under side a rough, ragged appearance. 

 These mostly vary in length from 10 to 40 mm , the upper ones longer; 

 the proliferous ones may bear branchlets 5-12 mm long and 4-6 mm in 

 diameter, with slender exsert axial coi'allites, 1.5 to 3.5 mm long, and 

 tubular, truncate, or labiate-tubular radial corallites, with the aper- 

 ture either terminal or oblique. On the lower branches are numer- 

 ous immersed corallites, about l mm in diameter, with rudimentary or 

 abortive septa, as in surculosa. 



The upper side is covered with rather slender, neatly tapered, 

 acute, forked or proliferous upright branchlets, their divisions rising 

 at an acute angle, and nearly parallel, as is well shown in Dana's 

 general figure of this specimen. Some of them bear 6 to 10 divi- 

 sions. The larger branchlets are 35 to 50 ram long, often 8 to 10 mm 

 thick at base, when simple or nearly so ; those toward the margins 

 are compressed and stouter. 



Axial corallites are rather small and slender, about 2 mm in diameter 

 and l-2 mm exsert; walls thin, reticulate-porous, strongly costulate ; 

 septa six, narrow, the directives usually a little wider. 



