458 j\Ir. G. Brook on new Spr-cies of 



LIV. — Descriptions of new Species of Madrepova in the 

 Collection of the British Museum. By George Brook, 

 F.L.S. 



During tlie examination of the collection of Madrepores in 

 the British Museum I have found a number of specimens 

 which, after careful comparison with types contained in other 

 European Museums, seem to me to be undescribed. In 

 anticipation of a fuller detailed account of the species of this 

 family, I offer the following abridged descriptions of the 

 new species. 



Maclrepora Brueggemanni. 



Madrepova laxa, Briig-gemann (uou Lamarck), Abli. uatarw. Ver. 

 Bremen, Bd. v. 1877, p. 544, 



Corallum spreading, arborescent, laxlj branched. Main 

 branches stout, 2 to 3 centim. tliick, elongate or short and 

 obtuse. Elongate branches 15 centim. long and I'S centim. 

 thick, little divided, scarcely tapering, except near the apex ; 

 stunted form of similar diameter, more frequently and divari- 

 cately divided ; ultimate divisions 2 to 3 centim. long, 1 to 

 1"5 centim. thick, scarcely tapering, very obtuse at the apex. 

 A few short conical buds or abortive branchlets are scattered 

 at intervals from the base upwards. Corallum rather dense, 

 surface strongly echinulate. Apical corallites very variable 

 in size, sometimes 4 to 6 millim. in diameter, with very thick 

 wall, not exsert or only slightly so ; at others conical, 2 

 millim. exsert, 4 to 5 millim. diameter at the base and about 

 3 millim. at the apex. In certain cases, where the terminal 

 divisions are very stout, a single apical corallite does not 

 occur, but, instead, the apex is occupied by several stout 

 cylindrical corallites, with only the rounded margin promi- 

 nent. This clearly is an approach to the condition in the 

 subgenus Isopora. Lateral corallites crowded, very unequal 

 and irregular on the upper surface, but distant below ; short, 

 thick, spreading, tubular, with small aperture and rounded 

 margin, 2 to 2'5 millim. diameter and 2 to 5 millim. long, but 

 most are short. At intervals certain corallites become more 

 elongate and thickened and form buds. The inner part of 

 the wall is often not so thick and prominent, in which case 

 the aperture opens inwards, and the outer part of the wall may 

 ]n-oject in a point or hooked knob some distance above it. 

 This type of corallite is most frequent in certain elongate 



