TRIBE III. MADREPORACEA. 483 



calicles, and a smooth surface. The branches are about two-fifths of an 

 inch in diameter, and the summit branchlets one-third to one-fourth of 

 an inch. The calicles have a smooth appearance ; but, under the micro- 

 scope, are seen to be very finely striate, with the striatures entire. 

 It grows a foot and a half, or more, high, and is alive for twelve or 

 fourteen inches. The branchlets are numerous, from one to four 

 inches long, with tapering apices. Below four inches, the calicles are 

 quite short. 



This species resembles the formosa, but is peculiar in its nariform 

 calicles. 



58. MADREPORA HUMILIS. (Dana.) 



M. humilis,fruticosa, crassa, late ramosa, subprotifera, ramis teretibus, 

 obtusis,fere J" crassis. Corallum caliculo apicali crassimo (scepe 2'" 

 lato), vix exserto ; lateraKbus csqualibus, et cequatiter subconfertis, 

 validioribus, bene nariformibus, aperturd oblongd, stelld vix conspicud, 

 lamellis duabus prominulis infrdquefere conniventibus. 



Low fruticose, spreading and short ramose, stout, subproliferous; 

 branches terete, obtuse, nearly an inch thick. Corallurn having 

 the apical calicle very stout (often 2 lines broad), scarcely exsert; 

 the lateral equal and even, somewhat crowded, very stout, neat 

 nariform ; aperture oblong; star scarcely distinct, two of the lamellae 

 most prominent, and nearly meeting below. 



Plate 41, fig. 4, corallum, natural size; 4 a, profile of calicle; plate 

 31, fig. 4 a, c, b, views of calicles, enlarged. 



Feejee Islands. Exp. Exp. 



This very short and stout species is remarkable for its evenly terete 

 and obtuse branches, and the neat regularity of its large and thick 

 nariform calicles, which become gradually smaller under the apex. 

 It grows in small clumps, five or six inches high, consisting of a few 

 branched stems, from a common base. In one specimen, the branches 

 are nearly two-thirds of an inch thick at base; and, in another, hardly 

 half an inch. 



