166 MADEEPOEAEIA. 



mode of branching, by the less crowded, more unequal radial corallites, which are also of 

 greater diameter and are not compressed. 



Pacific Ocean : Damley Island and Great-Barrier Reef. 



a. Damley Island. J. B. Jukes, Esq. [P.]. 46. 7. 30. 34. 1 



b-d. Wreck Bay, Great-Barrier Reef. J. B. Jukes, Esq. [P.] . 46. 7. 30. 13, 20 & 23. J ^^P^^* 



e. ? W. H. Ince, Esq. [P.]. 82. 11. 16. 2. (Var.) 



/. Low Woody Island. Saville-Kent Coll. 92. 6. 8. 124. 



165. Uadrepora plantaginea. 



Madrepora plantaginea, Lamarck (mow Dana), Hist. Anim. sans Vert. t. ii. p. 279 (part.), ed. 2, p. 447 ; 

 BlainviUe, Manuel d'Actin. p. 390 ; ? Quoy et Gaimard, Voyage de 1' Astrolabe, Zool. t. iv. p. 234, 

 pi. six. fig. 3 ; M.-Edwards & Haime, Coralliaires, t. iii. p. 149 ; VerriU, Bull. Mus. Comp. Zool. 

 1864, vol. i. p. 42 ; Ortmann, Zool. JB. 1888, Bd. iii. p. 151 ; ibid. 1889, Bd. iv, p. 504 {non 

 Dana, Zoophytes, p. 459 ; non Briiggemann, Phil. Trans, vol. clxviii. 1879, p. 576 ; rum Studer, 

 MB. Akad. Wiss. Berlin, 1878, p. 530 ; non Studer, Mitth. naturf. Ges. Bern, 1880, p. 19 ; non 

 Quelch, ' Challenger ' Reef Corals, p. 153). 



Madrepora variabilis, Ortmann, Zool. JB. 1888, Bd. iii. p. 152 (part.). 



A number of specimens which form part of Lamarck's collection in the Paris Museum 

 are labelled Madrepora plantaginea, but are referable to at least three species. One is 

 undoubtedly M. laxa, and agrees with the type specimen, and another perhaps belongs 

 to M. retusa, Dana. The one which I have selected for description appears to be that 

 described by Milne-Edwards. 



CoraUum cespitose, about 17 cm. broad and 12 cm. high. Branches simple or subdivided, 

 up to 7 cm. long and about 1-4 cm. thick. The majority of the radial corallites are short; 

 but many are thick, tubular, spreading at almost right angles, the more important of which 

 become proliferous and form short spreading branchlets. The terminal 1 to 1-5 cm. of a 

 branch often differs from the lower part in the absence of these proliferous corallites, and the 

 radial ones are more appressed. Axial corallites 4 to 5 mm. diameter, and about 3 mm. 

 exsert ; wall thick, margin rounded, aperture about 1 mm. Proliferous tubular corallites and 

 branchlets 3 to 13 mm. long, 2 to 4 mm. diameter or more, with rather thick wall. Radial 

 corallites 1"5 mm. diameter; wall rather thin, 2 to 3 mm. long; they are appressed tubular 

 above, but soon become shorter, and many are almost immersed at a point 2 cm. from the 

 apex, but still with the prominent proliferous corallites between them. The septa of the 

 axial corallites are in two cycles, both rather narrow ; in the radial corallites there are also 

 two cycles, but the directive septa are more prominent. CoraUum porous ; surface spongy- 

 echinulate ; wall substriate or echinulate in irregular longitudinal rows. 



Two other specimens, which are possibly referable to the same species, have fewer and 

 shorter spreading proliferous corallites, and thus the branches have a more regular 

 appearance. The radial corallites are mostly short, with the inner part of the wall thin and 

 rudimentary, the outer part thickened a little, and the margin rounded. Certain corallites. 



