72 MADEEPOEAEIA. 



little tortuous, 12 mm. thick below; branchlets often 5 cm. long and 4 to 8 mm. thick, 

 acuminate and subacute ; surface of the corallum scabrous, not at all striate. Axial 

 corallite 1'5 mm. long and broad; radial corallites obsolete below 7-5 cm. from the apex; 

 above short, round, nariform, rather distant and fragile ; star obsolescent, the directive septa 

 but slightly prominent. (Dana.) 



The Ponape specimen referred by Ortmann to this species is 16 cm. high and 24 cm. 

 broad ; branches 8 cm. long and 1 cm. thick, slowly tapering, often bent ; apices much 

 divided. Axial corallites 2 mm. diameter or slightly over, 1 to 2 mm. exsert, but provided 

 with very small buds to near the margin ; wall firm, aperture large. Radial corallites im- 

 mersed below, then very short, and finally, nearer the apex, nariform or tubo-nariform, 

 unequal in size. A few are proliferous, but scarcely longer than the others ; the longest 

 measure 4mm., and are often a little compressed, 1*2 to 1-5 mm. in diameter; surface 

 spongy, vermiculate, and echinulate ; wall finely striato-echinulate. The outer part of the 

 wall is often slightly thickened ; and small, thin, or tubular corallites, turned in various 

 directions, are scattered between the others to near the apex. 



The species appears very close to M. implicata ; and Dana's descriptions are insufBcient 

 for their proper separation. M. tortuosa has stouter branches, more prominent corallites, 

 and a number of small ones opening in various directions. Dana states that the surface 

 of the coenenchyma is not striate in the type specimen ; it is distinctly vermiculate in the 

 Ponape specimen recorded by Ortmann. 



Pacific Ocean : Fiji Islands, Ponap^ (Caroline Islands). 



57. Madrepora implicata. 



Madrepora implicata, Dana, Zoophytes, p. 466, pi. xxxvii. fig. 2 ; M.-Edwards & Haime, Coralliaires, 

 t. iii. p. 144 ; VerriU, Bull. Mus. Corap. Zool. 1864, vol. i. p. 41 ; Rathbun, Proc. U.S. Nat. Mus. 

 1887, vol. X. p. 19. 



Corallum 15 to 20 cm. high, cespitoso-arborescent, closely ramose ; branches crowded, 

 curved, and tortuously entangled, often coalescing, slenderly attenuate ; stems 8 mm. thick, 

 branches 4 mm. Corallum scabrous and striated, with linear pores. Axial corallite 16 mm. 

 in diameter. Radial corallites obsolete below 5 cm. from the summit ; above this short, 

 round, nariform or fragile, scattered ; star obsolescent. [Dana.) 



This species may prove to be a slender variety of M. tortuosa. 



Pacific Ocean : Fiji Islands. 



58. Madrepora pruinosa. (Plate XXXIV. fig. B.) 



Corallum cespito-arborescent, about 12 cm. high and 17 cm. wide ; branches 1 cm. thick, 

 7 to 9 cm. long, usually much divided. Axial corallites 2*75 mm. diameter, usually 2 mm. 

 exsert ; wall rather thin. Radial corallites immersed or subimmersed on the main divisions 

 and up to within 4 cm. of the summit, or at most with a few verruciform corallites ; more 

 distally the corallites are round, nariform or tubiform, about 2 mm. diameter and 1 to 25 mm. 



