54 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 149 



tem with four instead of two genital pores, higher, wider test, wider 

 paired petals, more divergent anterior paired petals, and wider peri- 

 stome. It differs from the Late Pleistocene .S\ (Paraster) eustatii 

 Engel (1961, p. 3) from St. Eustatius in the West Indies by its more 

 anterior apical system, narrower ambulacrum III, and more flexuous 

 anterior petals. 



Type.— Holotype USNM E10302. 



Occurrence. — This rare species was not found alive in its habitat. 

 Dead tests were found near the reef in about 35 feet of water (station 

 19), well beyond the reef on a sandy terrace in 80 feet of water (sta- 

 tion 17a), and landward of the reef on sandy bottom in only 15 feet 

 depth at station 30. Probably it lives buried beneath rocks or clumps 

 of sponge and coral, in a manner similar to that of Brissus unicolor 

 and Echinoneus cyclostomus, and therefore is rarely encountered. 



Kier found a dead test of the same species on a sandy bottom at 

 85 feet depth off the southern Caribbean island of Dominica. Because 

 the species has never been taken alive, its habitat preferences remain 

 unknown. 



ENEMIES OF ECIIINOIDS 



No general survey of the predator-prey relationships of echinoids 

 is intended here, but our observations of victimization of echinoids by 

 other animals are significant enough to warrant emphasis. The most 

 incontrovertible attack observed was that by the starfish Oreaster 

 reticulatus upon Mcoma ventricosa, as described above in the discus- 

 sion of that species (pi. 12, figs. 1,2). To our knowledge, this is the 

 first record that O. reticulatus may feed upon M. ventricosa. This 

 urchin also is attacked by the red band parrot fish (Sparisoma anro- 

 frenatmn) which nibbles away spines on the dorsal surface that are 

 not completely protected by a cover of sand (pi. 11, fig. 1). 



Other examples of fish predation were noted when specimens of 

 the thin sand dollars Encope michelini and Leodia sexiespcrforata 

 were overturned to see how they right themselves. When the urchins 

 wore nearly vertical, in the process of righting themselves, a little 

 burrowing fish nipped at the upturned edges. Many injured speci- 

 mens of these thin sand dollars were seen, some with nearly one- 

 quarter of the test broken away, but nevertheless healed and bearing 

 spines. Undoubtedly this breakage could have resulted from several 

 causes, one of which may be biting by fish. 



