MADEEPOEA. 63 



or less oblique, ascending, with the apex a little recurved, 3 to 4 mm. long, 1-5 mm. thick, 

 with a few smaller nariform or subimmersed ones between. A little distance below the apex 

 many of the prominent corallites are more spreading, 2 mm. thick, and bear a few small, round, 

 nariform buds ; in some parts these proliferous corallites are almost wanting, but in others 

 they are quite numerous and may occasionally give rise to branchlets 1 to 2 cm, long, in other 

 cases they form short rosettes similar to those of M. florida ; wall a little thickened, firm but 

 porous. Nearer the base of the branches the corallites are shorter, but completely immersed 

 ones are rare. The star consists of 12 septa, which are not well developed, but the directives 

 are moderately broad in the prominent corallites. Corallum moderately porous ; surface 

 reticulate and echinulate ; wall faintly striato-reticxilate and finely echinulate. 



Var. conica. (Plate XXX. fig. C.) 

 Corallum cespitose from a broad incrusting base. Branches spreading, short, thick, 

 conical, to 8 cm. long and 3 to 3"5 cm. thick, covered with "rosettes" and short 

 proliferations. A number of the rosettes, especially on the outer sides of the branches, 

 become elongate (1'5 to 4'5 cm.) and proliferous, the longer ones being situated near the 

 base. The aperture of the central corallite of a rosette is usually circular or nearly so, and 

 there is a general absence of the notched condition which occurs in M. florida. The surface 

 of the coraUum is reticulate and echinulate ; waU striato-echinulate. 



A specimen from the same locality without rosettes, but with numerous elongate tubular 

 corallites, with or without buds, appears to represent an earlier condition in the differentiation 

 of the colony in this variety. 



Pacific Ocean : Tongatabu. 



a. Tongatabu. J. J. Lister, Esq. [P.]. 91.3.6.6. (Type.) 



Var. conica. 



a, b. Tongatabu. J. J. Lister, Esq. [P.]. 91. 3. 6. 5 & 8. 



33. Madrepora florida. 



Madrepor a florida, Dana, Zoophytes, p. 466, pi. xxxvii. fig. 1 ; M.-Edwards & Haime, Coralliaires, t. ill. 

 p. 141 ; Eathbun, Proe. U.S. Nat. Mus. 1887, vol. x. p. 15. 



The following is Dana's description : — 



" Arborescent, very large, broad, and remotely ramose ; branches 1-25 in. thick, gradually 

 tapering, bearing over the surface small clusters of polyps. Corallum covered with calicular 

 tubercles ^ of an inch broad ; calicles unequal, very short tubiform, rather stout, striated ; 

 some tubo-nariform with immersed cells interspersed ; star 6-rayed, distinct, two of the lamellae 



not more prominent The rosettes consist generally of 6 to 10 very short calicles ; 



they cover regularly the whole surface. Between these rosettes the cells are mostly immersed." 



A number of specimens in the collection appear referable to this species, but all differ 

 more or less from the above description. 



I 



