366 BULLETIN 103, UNITED STATES NATIONAL MUSEUM. 



in the Hunterian Museum at that institution, and I have based the 

 following description on them : 



The corallum is head-shaped, M'ith a greater diameter of 107 mm. 

 and a lesser of 86. 



The calices are circular, 2 mm. in diameter, margins slightly ele- 

 vated, joined by equal costae, distance apart usually about 1 mm., 

 occasionally 2. 



Septa 24 in number, alternately larger and smaller; the larger are 

 rather thick and reach the columella; the intermediate ones are short 

 and their inner ends are free. 



Columella spongy, well developed, its diameter about one-third 

 that of the calice. 



A comparison of the photographs with specimens show^s that the 

 traditional Orlicella annularis of the Caribbean and Gulf region is 

 correctly identified. 



There are in the collection of the United States National Museum 

 a number of specimens that are ahnost duphcates of the type-speci- 

 men, except that they are not w^orn, as is the type. These specimens 

 form the basis of the succeeding description (see pi. 81, figs. 1, la). 



The corallum forms rounded masses rising above a rather large, 

 fii-mly attached base, which is, however, less in diameter' than the 

 maximum diameter of the corallum. Frequently there is a pro- 

 jecting or incrusting edge whose lower surface is covered by epitheca. 

 The upper surface may \>q uniformly rounded, undulate, or lobed. 

 The size, of course, is variable; the masses may be several feet in 

 diameter. 



The caHces are circular, or sHghtly deformed. Their diameter, 

 measured between thecal summits is from 2 to 2.5 mm. In depres- 

 sions on the surface they may be smaller, about 1.5 mm., but these 

 are abnormal. Their edges are from 0.5 to almost 2 mm. apart, 

 about 1 mm. is probably an average. The calicular edges are 

 slightly elevated. The intercorallite areas are costate. Costae cor- 

 respond to all septa; subequal or alternating in size, those of adjoin- 

 ing cahces meeting; edges dentate; thicker than the width of the 

 intercostal spaces and moderately elevated. 



Septa in thi'ee complete cycles, primaries and secondaries equal, 

 rather stout, extendmg to the columella and fusmg to it; tertiaries 

 shorter, about half the length of the primaries, somewhat thinner, 

 inner edges free. Margins of the primaries and secondaries decid- 

 edly exsert; their inner edges fall perpendicularly to the bottom of 

 the calicular fossa, and bear just above the columella one or two 

 prominent teeth, with a few smaller teeth above; the septal arch is 

 either very gentle, obtuse, or it may be truncate, its dentations fine; 

 the outer margins steep, but more inclined than the inner, dentations 

 relatively coarse. Septal faces finely granulate; in longitudinal 

 cctions, the inner edges are lacerate, the last cycle with perforations. 



