A. E. Verrill — Comparisons of Coral Faunm. 195 



mens, 15 to 30™™ broad, the collinos are less acute and prettj^ 

 regularly concentric around a larger, regular, central, primary 

 calicle. 



The septa are mostly in three cycles, and of three different sizes ; 

 the number varies from 20 to 32. The primaiy and secondary septa 

 are thickened, especially distally, but the primaries are wider and 

 thicker proximally than the others ; tertiaries are much narrower 

 and thinner ; all are finel}^ and sharply granulated laterally, and a 

 little exsert. They are not so much crowded as in typical agaricites, 

 and are more unequal in size and thickness. The central pit is deep 

 and narrow. Columella is small, solid, umbonate. 



Diameter of ordinary calicles 1.5 to 2.5™™ ; of central one, about 



According to Prof. Hartt it never becomes more than two or three 

 inches broad. Our largest specimen is 65™™ broad, partially cover- 

 ing a rather thickish frond of partially dead coral of the same kind, 

 which appears to have been repeatedly nearly killed and then 

 renewed by outgrowths. It shows no tendency to form upright 

 crests or fronds, but one edge is free for a breadth of 30'"™, but of 

 this only -1 to 6™™ was living. 



The other specimens are young. The smallest is a simple primary 

 corallite, 4™™ in diameter, closely sessile, even to the edges ; it has 

 four cycles of unequal septa. The next larger (on the same Mussa) 

 is 15™™ broad, with a larger primary central calicle and two con- 

 centric circles around it, with some of the third circle on one side. 

 This is also closely adherent and incrusting to the very edge, 

 except at one place, Avliere the edge is free for 2 to 3™™. In this 

 the inequality in thickness of the cycles of septa is very marked. 



This form may prove to be a distinct species when a larger series 

 can be studied, but with my small specimens the distinctive charac- 

 ters seem very slight, and may be largely due to immaturity, or to a 

 dwarfed state, owing to unfavorable conditions of growth. 



It agrees better with a young specimen from Key West, Florida 

 (pi. xxvii, figs. 2, 2a, No. 103), than with any of the other West 

 Indian forms that I have. But the latter has larger calicles ; much 

 higher and larger collines ; thicker, closer, and less unequal septa ; 

 more finely and evenly striated exterior ; and a less closely incrust- 

 ing mode of growth. I have considered the latter a j^oung stage of 

 the typical agaricites. 



The var. pusilla, from Colon, has decidedly smaller calicles and 

 collines, and appears more like a depauperate variety of agaricites. 



