Madrepora in the British Museum. 467 



cinna in habit. Branches complanate below, the basal parts 

 fused into a solid plate with immersed corallites ; distal parts 

 with liemicotyloid corallites and a few lateral, tubular or 

 conical ones. Branches on the upper surface about 4 centim. 

 long and 1*3 to 1*5 centim. thick, angular below, with 

 crowded immersed corallites ; often divided above into two to 

 four branchlets, many of whicli, especially near the centre of 

 the corallum, bear numerous ascending proliferations. Apical 

 corallites 2*5 to 3 millim. diameter, rarely over 1 millira. 

 exsert, margin scarcely rounded. The central branchlets bear 

 crowded {iroliferations, 7 millim. long and 4 millim. thick, 

 with crowded immersed corallites between ; others are dimidi- 

 ate and appressed, 2-5 to 4 millira. long and I'O millim. 

 thick ; wall thin but tirm. The peripheral branchlets have 

 few proliferous corallites ; most are subequal, nariform, with 

 an elongate lip, and a little compressed, 3 millira. long and 

 1'3 millim. thick. Star moderately prominent, the directive 

 septa very broad. Corallum rather porous, surface tinely 

 echinulate, wall striato-echinulate. 

 Mauritius. 



Madrepora procunibens. 



Corallum prostrate or subprostrate, subdivisions free. 

 Branches up to 16 centim. long and 1 centim. thick, bearing 

 ramiculi I'd to 3'5 centim. long, each of which is usually 

 produced from a single tubular corallite by the formation of 

 lateral corallites upon it, nariform or tubo-nariform at first, 

 but becoming spreading tubular, 4 to 9 millim. long. There 

 may be twenty or more on a twig 3 centim. long, radiating 

 in all directions, tlie longer ones arched and bearing very 

 short nariform buds. The stem and main branches bear a 

 few corallites at irregular intervals, nariform or subiraraersed 

 and immersed. The elongate tubular corallites are 2 millim. 

 diameter near the base and Vb at the apex. Apex suddenly 

 contracted ; aperture small, enclosing a star of six well- 

 developed septa. Corallum dense, surface finely echinulate, 

 not pitted, wall echinulate in rows. 



This species comes near to M. longicyathus, and may prove 

 to be only a well-marked variety of it. It differs, however, 

 in habit and in the arrangement and number of the corallites 

 on the branchlets ; the axial corallite also usually bears buds 

 to within 2 millim. of the apex, whereas in M. longicyathas. 

 the terminal 7 millira. is usually free. In one specimen the 

 branches extend horizontally, in another obliquely. 



South Seas. 



