A. E. Yerrill — Comp<.i)-isons of Coral Fmmce. • 193 



This cannot properly be retained in Acanthastrcea, for it increases 

 by median and snbniedian fission. The calicles are very irregular, 

 varying from circular to oblong-elliptical, hour-glass shaped, three- 

 lobed to five-lobed, etc. They often have three or more centers. 

 They are also very variable in size. Where the calicles are crowded 

 the walls are completely united, thin and solid ; in some other places 

 they are united by cellular exotheca and costal 



The mode of growth and forms of the calicles are like several 

 species of Mussa, especially M. hispida V, and M. rigida D., to 

 which it is evidently closely allied. From the former it differs 

 chiefly in the smaller size of the calicles, the reduced columella, the 

 fewer and less laciniate septa, and the thinner walls, solid or with 

 little exotheca. 



But the larger and somewhat paliform teeth at the base of the 

 septa cause it to resemble some species of Favia, very decidedly. 

 It might, in fact, be referred to that genus without hesitation by 

 some writers, for it is in- several ways an intermediate species. But 

 it seems to lack true paliform lobes or teeth. It appears to be related 

 more directly to Mussa tenuisepta V. and M. Harttii, which inhabit 

 the same region. It may, then, be considered a Favia-W^e Mussa, 

 with unusually small and well isolated calicles for a 3Iussa. 



Abrolhos Reefs, type. No. 14(jV, Porto Seguro, Sta. Cruz, Bahia ; 

 Maceio, low tide to 15 feet or more, abundant (C. F. Hartt). 



Mussa (Symphyllia) tenuisepta Ver., sp. nov. See p. 127. 

 Plate xxi, figure 3. 



Coral massive, astreiform, with the corallites mostly isolated and 

 united to the edges of the calicles by costse and cellular exotheca, 

 the division walls usually showing a superficial furrow at the surface. 

 Proper calicinal walls very thin. Under side closely adhei'ent to 

 very near the edge in the types ; the exterior costse, where visible, 

 are thin, elevated, and lacerately spinulose. 



Calicles moderately large, diameter mostly 15 to 25™™, average 

 about 20™™, rather shallow, rapidly narrowed to the bottom, irreg- 

 ular in form. Many of the smaller ones are rounded, but the larger 

 ones are mostly lobulate, with two to four lobes, and many are 

 undergoing median or submedian fission. A few small calicles seem 

 to have arisen from exothecal buds. 



The septa are thin, numerous, rather crowded, not very wide, little 

 exsert, with their thin inner edges sloping and deeply laeiniately 



Trans. Conn. Acad., Vol. XI. 13 December, 1901. 



