Distribution of Littoral Echinoderms of the West Indies. 61 
None of the above species, when adult, is at all difficult to recognize 
nor is any one of them of doubtful authenticity. The two species of 
Clypeaster are quite unlike and the same is true of the Encopes and 
Mellitas. The two Echinometras are more liable to confusion because 
E. lucunter is so variable in form, length of spines, and color, but no 
one who has once seen typical viridis will have any difficulty. The 
cassidulid, Rhynchopygus caribearum (Lamarck), is probably a littoral 
species, but it is so rare and little known that I have not ventured to 
include it in the above list. On the other hand, the spatangoid, Schi- 
zaster orbignyanus A. Agassiz, is probably not a littoral species, but I 
found a bare test under a rock in shallow water at Montego Bay, 
Jamaica, in March 1912, and it may possibly be truly littoral. It is, 
however, a very rare and little-known species. 
Of the above littoral species, Echinoneus cyclostomus seems to be 
tropicopolitan; at least it is known from not only the West Indian 
region but throughout the Indo-Pacific from Mauritius to Hawaii 
and Easter Island. 
Of the remaining 17 species, 9 have a general tropical Atlantic 
distribution from the Carolinas, or Florida at least, to Brazil. Of these, 
5 are already known from the eastern Atlantic and at least two of the 
others will probably be found there. One of the 9 (Brissus) is not 
yet known from Brazil, but it almost certainly will be found there. 
These are the 9: 
Eucidaris tribuloides. Clypeaster subdepressus. 
Centrechinus antillarum. Mellita quinquiesperforata. 
Lytechinus variegatus. sexiesperforata. 
Tripneustes esculentus. Brissus brissus. 
Echinometra lucunter. 
It is a remarkable fact that there is not a single echinoid that can 
be called distinctively West Indian, unless possibly one or two of the 
following group, which seems to have a northern range, should prove 
to extend further south than is at present known. This northern group 
mcludes 7 of the remaining 8 species, as follows: 
Arbacia punctulata. Moira atropos. 
Echinometra viridis. Plagiobrissus grandis. 
Clypeaster rosaceus. Meoma ventricosa. 
Encope michelini. 
Of all these, Arbacia has the most peculiar distribution, for its 
range seems continuous from the Tortugas and Florida northward 
along the coast to southern Massachusetts. It does not occur at 
Bermuda nor is it known from the Bahamas, but it is recorded from 
both Cuba (northwestern coast only) and Hayti (an old record that 
needs verification). It does not occur at Jamaica, nor is it known 
from Porto Rico or the Lesser Antilles, but it does occur in Trinidad 
and Tobago. It occurs on the coast of Yucatan and has been reported 
