232 A. E. Verritt — Corals of the Genus Acropora. 



are rather large (1 to l*25 mm ), and regularly stellate, with six well- 

 developed primary septa and six narrow ones; the directives nearly 

 meet in the center. 



On the more distal parts, and especially on the terminal branches, 

 the margins of the calicles become more elevated, especially on the 

 lower side, forming thin lower lips that stand out often nearly at 

 right angles, but unevenly so, thus giving the surface a rough and 

 irregular appearance. 



Those near the ends of the branches are often tubular, but entirely 

 adnate, with the large, terminal, round calicles opening upward; 

 the inner lip being thin and very short or adherent, while the thin 

 outer lip is tubular and truncate. A little lower down the inner lip 

 is suppressed and the outer lip is shorter and often half -tubular or 

 dimidiate, but the calicles are nearly round and often open rather out- 

 ward, so that they are conspicuous in a side view. They are rather 

 crowded and unequal in size, the larger ones being about l.25 mm in 

 diameter. All the larger ones have 1 2 septa, but the septa may all 

 be rather narrow, except the directives, which are usually well 

 developed. 



The walls are always thin, compact, and strongly costulate. The 

 ccenenchynia is firm but porous, irregularly pitted, and covered with 

 rather loosely arranged, small, rough granules. 



Manilla Bay, Luzon. The type is in the Mus. Yale Univ. (No. 

 1809, orig. number 108), received from the Museum of Comp. Zool- 

 ogy, where there were formerly many specimens. 



This species belongs to the subgenus Eumadrepora of Brook. It 

 is, perhaps, more nearly allied to Acropora pulchra, var. stricta 

 Brook, than to any other form described by him, but the latter has 

 smaller and more tubular corallites, and the surface is " closely 

 reticulate." 



Acropora microphthalma Ver. See p. 216. 



Madrepora microphthalma Verrill, Comm. Essex Inst., vi. pp. 83, 102, [4!>. 

 68,] 1869. Brook (pars), p. 168. 



Plate XXXVI C. Figure 1. Plate XXXVI F. Figure 15. 



The specimens referred to this species by Brook (p. 169) appear to 

 be quite - distinct. They are "laxly arborescent; branches elon- 

 gate, 2 cra thick ; scarcely tapering," and have much larger radial 

 corallites, which are "dilated, tubular," with the inner part of the 

 wall "often incomplete or absent." 



