MADREPOBARIA WHITELEGGB. 359 



summits; they are funnel-shaped, 2'5 mm. in diameter, 1*5 to 3 

 mm. in length, with an aperture of about 1 mm. Corallite walls 

 porous, faintly striate, and denticulate ; the striae 0'2 mm. apart, 

 the denticles 0-15. Outer margin stout, inner thin, rarely incom- 

 plete except near the summits of the branchlets. 



Axial corallites 2 to 3 '5 mm. in diameter, 2 mm. exsert, with 

 thin walls, a large aperture, and twelve septa, narrow above and 

 broad below. 



MADREPORA SPINULIFERA, sp. nov. 



Coral lum prostrate, openly reticulate ; mesh from 2 to 3 cm. 

 long, and 1 cm. wide. Main branches angular, 1 cm. in diameter. 

 Under surface without branchlets, upper with a series of short 

 ones set at an angle of fifty degrees and directed outwards ; they 

 are 5 mm. in diameter at the base, 1*5 cm, in height, and 1*2 cm. 

 apart at the apex. Inner branchlets simple or with incipient 

 twigs, tapering a little to their frequently compressed apices. 

 Outer branchlets subcylindrical and more or less proliferous near 

 their summits. 



Corallites of the under surface of the branches immersed or 

 subimmersed, becoming depressed nariform a short distance from 

 the extremities ; they are about 2 mm. apart, 1 mm. or less in 

 diameter, and have a round or oval aperture. 



Calicles very deep, with twelve septa all narrow except the direc- 

 tives, which are broad and but rarely meet below. The secondaries 

 are occasionally rudimentary in the young corallites. 



The corallites of the upper surface of the branches and bases of 

 the branchlets are similar to those on the under, but are wider 

 apart, usually about 3 mm. 



Radial corallites of the branchlets nariform, compressed inner 

 wall often incomplete, tubo-nariform only in buds destined to 

 form branchlets ; aperture oblique, opening upwards, longer than 

 broad or more frequently twice as long as broad ; septa six, the 

 directives large ; length 2 to 3 mm., diameter 2 mm. at the base. 



Axial corallites compressed; 1*5 mm. in their shorter and 2*3 

 in their longer diameter ; aperture elliptic, frequently narrowed 

 in the middle. 



Septa in two cycles, the secondaries narrow, the directives 

 broad and nearly meeting below. 



Surface of corallum porous, minutely spinulose ; spinules com- 

 pressed, acute at the apex, 0*2 mm. high and about the same 

 distance apart. Corallite wall thin, porous within and without, 

 striate; the striae (H4 mm. apart; base and marginal lip beset 

 with spinules similar to those on the rest of the surface ; inter- 

 mediate portion of wall with spiniform granules. 



