96 A. E. Verrill — Bermudian and West Indian Reef Corals. 



from what he there says of the size of the calicles, and also when, 

 on p. 326, he compares the stars of M. porites with those of his 

 astroites, and says they are subequal. 



This species occasionally shows certain calicles larger than usual, 

 and with more septa. Such calicles may subdivide by regular fission, 

 as is the case with the similar unusually large cells in some species 

 of Porites, Madrepora, Pocillopora, etc., in which fission is elsewhere 

 very unusual. One of our Bermuda specimens shows such a cell in 

 the very process of subdivision, (pi. xv, fig. 1, a). 



This coral occurs on the outer reefs of the Bermudas, but it is not 

 common there. It is very common and grows to a large size on the 

 Florida Reefs, in the Bahamas,* and throughout the West Indies. 



When well grown it forms hemispherical or spheroidal masses, up 

 to five feet or more in diameter. But it also grows in irregular 

 incrusting plates, and sometimes in nodose or lobulate masses, or 

 «ven in branched forms. 



Mr. A. Agassiz in the work quoted, 1890, has given some interest- 

 ing data as to its rate of growth. Other data were given by me in 

 Proc. Boston Soc, x, p. 862, and in Dana's Coral Islands, p. 125. 



Variety, stellulata (Dana, ex. Ellis and Sol.). 



Heliastrcea stellulata Edw. and Haime, Hist. CoralL, ii, p. 473, 1857. 

 ? Cyphastroia oblita Duch. and Mich., Corall. Ant., p. 77, 1860. 



Plate XV. Figure 2. 



The two types of Dana's stellulata are in the Museum of Yale Uni- 

 versity. They are beach-worn specimens of a true Orbicella, more or 

 less infiltrated with calcium carbonate, to which the unusual solidity 

 of the walls and exotheca, in some parts, as seen in sections figured by 

 Dana, seems to be partly due. In other parts the structure is nearly 

 as in O. annularis, to which it probably belongs, though there are 

 differences in the sections not due to infiltration. Its septal arrange- 

 ment is the same as in ordinary specimens of the latter, those of the 

 third cycle being distinct, but narrow and thin. The borders of the 

 calicles seem to have been but little raised, and the septa rather 

 thinner than usual, and not much exsert, but the poor condition of 

 the specimens renders these characters rather uncertain. 



The calicles are rather smaller (2 to 2-5'"'" in diameter) than is usual 

 in O. annularis. The thin septa are in three regular cycles ; those 

 of the third cycle are very thin and reach only one-fourth or one- 



* There is a fine Bahama specimen, about four feet in diameter and three in 

 height, in the Amer. Mus. , New York (coll. R. P. Whitfield). 



