Distribution of Littoral Echinoderms of the West Indies. 53 
]. WEST INDIAN LITTORAL ECHINODERMS. 
Recent echinoderms fall so readily into their five classes, without 
any disconcerting annectant forms, that it is easiest and most natural 
to discuss each class separately. 
COMATULIDA. FEATHER-STARS. 
At Tobago we found a comatulid, Tropiometra carinata (Lamarck), 
common in very shallow water in Buccoo Bay and on Buccoo Reef. 
It is a species of wide distribution on the coasts of southern Africa and 
Brazil, and reaches its northern limit in deep water (200 to 300 fathoms) 
off St. Lucia. As a littoral species, its northern limit seems to be at 
Tobago. The only other littoral comatulids of the West Indies are 
species of the genus Nemaster, though Mr. A. H. Clark tells me that 
the little-known Antedon diibenii Bohlsche, of Brazil and St. Thomas, 
appears “to be from very shallow water.” The remarkable and 
unique occurrence of Nemaster iowensis (Springer) at the Tortugas 
‘Gn water less than 3 feet deep” in 1893, is one of the most curious 
facts of distribution which the West Indian region affords. Its mystery 
is only deepened by the apparent occurrence of the same species at 
Bermuda. Mr. A. H. Clark very kindly permits me to thus note the 
fact that he has a specimen from that northern point. It is certain 
that other species of Nemaster occur in the West Indies, as is indicated 
by material in the United States National Museum, but as yet our 
knowledge of the genus is too fragmentary to make it of any use in 
discussing distribution. So Tropiometra is the only comatulid at 
present of value for this purpose and its occurrence at Tobago dis- 
tinguishes that island at once from the other West Indies. 
ASTEROIDEA. SEA-STARS. 
The littoral sea-stars of the West Indies are not numerous in species 
or abundant as individuals, and it is only occasionally or under special 
conditions that a species can be called common. Under favorable 
conditions, in particular spots, Astropecten duplicatus is very abundant, 
but these spots are as a rule in water more than 3 fathoms deep. On 
the other hand, Asterina folium occurs at or just above low-water 
mark, on particular reefs, in sufficient numbers to warrant calling it 
common, and the same is sometimes true of young individuals of 
Linckia guildingii, and at Bermuda it is true of Coscinasterias ten- 
uispina. At Port Royal, Jamaica, Echinaster sentus is fairly common 
and Oreaster reticulatus is by no means rare. Verrill reports the latter 
species as “very common in the Bahamas.” No other sea-stars can 
be called common in the shallow waters of the West Indies, but 
Ophidiaster guildingii is widely distributed and is by no means rare on 
the Tortugas reef-flats and on Buccoo Reef, Tobago. 
