352 Verrill, N'otes on Radkita. 



or not previously known to occur upon that coast, that it is believed 

 to be of interest to publish a complete list of all the species observed. 



Mr. Hartt has also greatly increased the value of the catalogue 

 by adding notes upon the distribution and stations of the species. 



It appears somewhat remarkable that while the Echinoderms, with 

 few exceptions, are common West Indian or Florida species, the corals 

 are nearly all, so far as known, peculiar to the coast of Brazil. This 

 is, however, in accordance with similar facts observed in the Pacific 

 and Indian Oceans, where the greater part of the tropical Echinoderms 

 have a vast range, in some cases even from the Hawaiian Islands to 

 the Coast of Africa, while the corals are much more local, all the 

 principal groups of Islands having many peculiar forms. 



This is, perhaps, chiefly due to the much longer time during which 

 the young of most Echinoderms remain in the free, swimming con- 

 dition, liable to be carried great distances by currents. 



A suite of the dupliisates, including all the species enumerated, 

 with the exception of two, has been presented to the Museum of 

 Yale College by Mr. Hartt. The first set he has retained in his own 

 collection. 



Class, POLYPI. 



Order, MADREPORARIA. 



Agaricia agaricites ? Edw. and Haime, CoralUaries, vol. 3, p. 81. 



Two young specimens that may belong to this species occurred 

 adhering to Mussa Harttii from the Abrolhos Reefs. They are, 

 however, too young to be satisfactorily determined. 



This species never grows to be more than two or three inches in diameter. It is 

 very frequently found attached to Mussa in shallow water. Occasionally it occurs in 

 the holes in the reefs and is almost laid dry at low water. — c. f. h. 



Siderastraea stellata Verriii, sp. nov. 



Corallum forming rounded or hemispherical masses, often flattened 

 above, cells polygonal, rather large (about "15 inch), deep, the central 

 part rapidly descending. Septa in four cycles, those of the first two 

 cycles considerably broadest, all of them evenly crenulated, rather 

 thin, thickness less than that of the intervening spaces, slightly pro- 

 jecting, the inner edge evenly rounded. Columella inconspicuous, 

 represented only by one or two tubercles. Wall between the cells 

 thin, represented by a single line. Trabicular processes between the 

 septa very plainly visible from above. 



Diflers from S. radians in having larger cells, which appear more 

 open ; thinner septa, and consequently wider intervening spaces ; and 



