164 A. E. Verrill — Bermudian and West Indian Reef Corals. 



Acropora Oken (restr.). Type, A. murieata. 



Madrepora (pars) Lara., Syst. Anim., p. 371, 1801 (non Linne, ed. x). Lara., 

 Hist. Anira. s. Vert., ii, p. 277, 1816. Dana, Zooph., p. 435, 1846. Edw. 

 and Haime, Hist. Corall. , iii, p. 132, 1860 (non Ehr.). 



Acropora (pars) Oken, Lehr. Naturg., p. 66, 1815 (type, 3d species = A. muri- 

 eata). 



Heteropora Ehr., Corall. Eothen Meeres, p. 333, 1834 (non Blainv., a Polyzoan). 



Madrepora Eathbun, R., Catal. Genus Madrepora in U. S. Nat. Mils., Proc. 

 U. S. Nat. Mus., vol. x, pp. 10-19, 1887. Klunz., Corall. Roth. Meeres, ii, 

 p. 2, 1879. 



Madrepora Brook (with ten subgenera), Cat. Mad. Brit. Mus., i, p. 22, 1893. 



Isopora Vaughan, op. cit. , p. 68, 1901. 



On pp. 110-113 I have discussed the use of the name JIadrepora, 

 and its inapplicability to this great genus for which it has so long 

 been used, if we are to follow the strict rules of priority and go 

 back to ed. x of Linne. 



The substitute-name that has the prior claim for adoption, and 

 which seems available, is Acropora Oken, 1815. This originally 

 included three generic tj^pes. The 1st is Pocillopora damicornis ; 

 2d is a Porites ; 3d is A. murieata (L.). 



The first two having been eliminated by Link and Lamarck, 

 Acropora can be restricted to the third species, which is the true 

 West Indian murieata. 



Vaughan used the much later and objectionable name Isopora 

 Studer, 1878, originally applied to a small section of the genus in 

 which the axial corallifes are indistinct or clustered. This is so 

 exceptional a character that the group may hereafter be separated 

 as a genus. Heteropora Ehr. was preoccupied by Blainville. 



The most prominent character of the genus Acropora is the exist- 

 ence of a special axial corallite, at the end of each branch, usually 

 larger and more symmetrical than the radial corallites that bud out 

 from its sides and cover the lateral surfaces of the branches. 



The latter are various in shape, but are nearly always more or less 

 one-sided and bilabiate ; except a few that are to become axial coral- 

 lites of new branches. 



On the under surfaces or on the bases of the branches, or in 

 crowded positions, whei*e the conditions are unfavorable, their prom- 

 inent margins may be obsolete, or nearly so, or they may be wholly 

 immersed in the coenenchyma. 



The septa are usually in two c} r cles, those of the second cycle 

 being smaller, and often rudimentary or lacking. In the lateral 

 corallites the directive septa are usuall}" wider than the others. 



