62 Papers from the Department of Marine Biology. 
from Brazil; the latter record, however, is probably due to confusion 
with the Brazilian species, Arbacia lixula (L.). This distribution is 
quite incomprehensible, but comparison of specimens from Tobago, 
the Tortugas, and Massachusetts shows no reason to doubt that all 
are punctulata. 
The range of Echinometra viridis is quite restricted, extending only 
from the Tortugas to St. Thomas, but Clypeaster rosaceus ranges 
northward along the coast to South Carolina, southward at least to 
Guadeloupe, and is common in the Bahamas. The range of Encope 
michelini is like that of Echinaster tenuispinus, from the Tortugas 
northward along the west coast of Florida and thence westward along 
the Gulf Coast to Mexico. The remarkable spatangoid Moira has a 
peculiar distribution, being common at Beaufort, North Carolina, but 
known also from Florida, Texas, Jamaica, St. Thomas, and Gaude- 
loupe. The finest of all spatangoids, Plagiobrissus grandis, is common 
near Nassau, Bahama Islands, but reliable records from elsewhere 
are rare; it is said to occur at Tampa, Florida; a fragment is known 
from the Tortugas, and there is a specimen recorded in the “Revision 
of the Echini” from Mexico. The range of Meoma is much greater, 
extending from Central America, Florida, the Bahamas, and Jamaica 
to Guadeloupe. 
The only remaining echinoid, Encope emarginata, appears to have a 
rather southern range, occurring from Uruguay to Venezuela and 
even to Martinique. It is reported from Charleston, Florida Gulf 
Stream, Nicaragua, and Yucatan, but these records are old and indefi- 
nite and are probably erroneous. 
HOLOTHURIOIDEA. HOLOTHURIANS. 
The holothurians are, next to the brittle-stars, the most abundant 
of the littoral echinoderms of the West Indies, but as they are not 
easily preserved and as preserved material is not attractive or inter- 
esting in appearance, they are as yet very inadequately known. They 
can be accurately determined only by an examination of the calcareous 
particles in the skin, and the study of these often involves the high 
power of a microscope. Moreover, we know as yet little about the 
growth-changes in holothurians, particularly as regards these cal- 
careous particles, and hence identifications made years ago are of 
doubtful validity, while many of those made to-day are merely tenta- 
tive. Many common West Indian holothurians are as yet unnamed 
and very few are adequately described. The following list of 24 species 
includes all those named forms, which are recognizable with sufficient 
ease and certainty to make the records of their occurrence reasonably 
reliable. It may be of interest to mention that there are in the M. C. 
Z. collection more than 25 additional littoral species, chiefly from the 
Tortugas, Jamaica, and Tobago, which seem to be undescribed and 
