348 HAWAIIAN AND OTHER PACIFIC ECHINI. 



specimens of albus, collected at various points on the Chilean coast, from Shoal 

 Bay, Patagonia, northward, chiefly by the "Hassler", shows- that that species 

 is very variable in all those characters by which bullatus is supposed to differ. 

 But with only a single authenticated specimen of hullatus at hand, its title to 

 recognition is not clear. It is supposed to be characterized by having all the ocu- 

 lars exsert but this is true of more than half the specimens of albus, and by 

 having only 7 or 8 pairs of pores in an arc instead of 9 or 10, but specimens of 

 albus occur which have only 8. The color of bullatus is also supposed to be less 

 green and more brown than albus but specimens of the latter are sometimes 

 more brown than green. In the face of these facts the status of bullatus cannot 

 be decided. Loxechinus is an interesting genus for several reasons. Its geo- 

 graphical isolation on the western coast of southern South America is notice- 

 able. It combines remarkably unspecialized globiferous pedicellariae with a 

 very high specialization of the ambulacra, while the character of the abactinal 

 system is apparently not at all firmly fixed as yet. It reaches an unusually 

 large size and develops an exceedingly thick test, and finally it is one of the 

 very few genera of echinoderms which are of use to man, its type species being 

 the edible "erizo" of Peru and Chile. 



CiENOCENTROTUs,^ gen. nov. 



Type-species, Echinus (Toxopneusles) gibbosus L. Agassiz and Desor, 1846. Ann. Sci. Xat., (3), VI, 



p. 367. 



Plate 95, figs. 16, 17. 



It is a remarkable fact that although this genus is nearer to Loxechinus geo- 

 grai)hicully tluui to any other genus of the family, it does not seem to be very 

 near it structurally but differs from it very strikingly. The only known species 

 is common on the coast of Peru, especially at Payta and it is also known from the 

 (Iala])agos Islands. In the very great majority of adult .specimens, a parasitic 

 cral) lives in the pcriproct, whicli is thereby more or less distorted. Whotlior 

 tliis i.s the cause of the unusual arrangement of the ocular plates by wiiich ocular 

 I is iu^\(M' ins(Mt unless all the othoi'^ are also, is not yet definitelv determined. 

 It is unknown how large a proportion of the individuals of a given se;ison reach 

 adult size without being parasitized antl also what the typical arrangement of 

 the oculars is for such adults. 



> Kuii'ds = now, strange + KcVrpov = prickle. 



