MADREPORARIA WHITELEGGE. 363 



The base is somewhat flattened, subcircular in outline, and 22 

 cm. in diameter ; it exhibits zones of growth enclosing dead 

 material, probably of the same species. 



The whole of the living layer appears to be incrusting, about 

 1 cm. or less in thickness, and is characterised by an extremely 

 uneven surface, beset with numerous irregular nodular elevations. 

 The larger elevations are from 5 to 6 cm. in diameter and about 

 the same in height ; the smaller are about 3 cm. in diameter and 

 2-5 cm. high ; they are scattered over the whole surface of the 

 corallum. 



The apertures of the corallites are situated at the bottom of 

 deep funnel-shaped pits ; they are about 1 mm. or less in diameter. 

 The raised ccenenchymatous walls are confluent, with thin, acute, 

 or rounded margins. They range between 1 and 2 mm. in diameter 

 at the summits, and are about the same in height. 



The surface is finely porous and echinulate ; the echinulse are 

 usually compressed and single-pointed ; they are about O17 mm. 

 high, and the same distance apart. 



There are twelve well developed septa; the primaries are usually 

 0-3 mm, broad at the margin and meet in the centre below ; the 

 secondaries are narrower, about O2 mm., and are often united to 

 the primaries near the columella. 



MONTIPORA VERRUCOSA, Lam. 



Montipora verrucosa, Lam., Hist. Anim. sans Vert., ii., p. 271, 

 1816. 



Montipora planiuscula, Dana, Zoophytes, U.S. Explor. Exped., 

 p. 507, pi. xlvii., fig. 3. 



There are three specimens of this species, all of which are in- 

 crusting, forming irregular convex cushion-shaped masses. 



The largest example is broken ; it is 22 cm. long, 10 cm. broad, 

 and 3 cm. thick, thinning down to about 7 mm. at the pendant 

 margin. 



The calicles are deeply sunk between the elevated papillae ; they 

 are usually about 1 mm. in diameter, possessing a very distinct 

 star of twelve septa ; the secondaries, although narrow at the 

 margin, frequently reach and unite with columella like the pri- 

 maries. A few of the larger calicles, near the centre of the 

 corallum, have an incomplete third cycle. 



The papillae are absent on the under surface ; on the upper 

 they are very variable in size ; in some parts they are thin, com- 

 pressed, and confluent at the base, in others they are thick, high, 



