BERMUDA ECHINODERMS. 131 



3. Ophionereis reticulata (Say). 



Disc covered with fine overlapping scales ; in other respects 

 like No. 6, but easily distinguished by the disc which is finely 

 reticulated with dark lines. Very common, occurring in bunches 

 in the sand and underneath rocks. 



4. Ophiostigma isacantha (Say). 



Disc coarsely granulated : arm spines 3, short and smooth ; 

 no tooth papillae. Color whitish, the arms ringed with green. 

 Rare. 



5. Ophiocoma echinata (Lamk.). 



This, the largest brittle star found in Bermuda, may be easily 

 recognized by the very dark color and very spiny arms. The 

 disc is an inch or more across and the arms are several inches 

 long. Found under rocks on sandy shores but not very common. 



6. Ophiocoma pumila Ltk. 



Smaller than the preceding ; disc granular, half an inch 

 across. Arms long, slender and spiny. Arm spines 4-6. 

 Color brownish-yellow, the arms banded with dark. The 

 specimens before me from Bermuda all have six arms. Not 

 common. 



7. Ophiomyxa flaccida (Say). 



Disc and arms covered with a thick naked skin ; arm spines; 

 stout and thorny; large; color very variable, orange to olive 

 green. Rare. 



ECHINOIDEA. SEA-URCHINS. SAND-DOLLARS. 



1. Cidaris tribuloides (Lamk.). 



This sea-urchin is seldom more than two inches in diameter, 

 and may be very easily recognized by the stout, club-shaped 

 spines. Common about the reefs off shore. 



2. Diadema setosum Gray. 



A large black sea-urchin with sharp, slender spines six inches 

 long or more. Sometimes the spines are banded black and 

 white. Common about the reefs off shore. 



