HAWAIIAN AJSTD OTHER PACIFIC ECHINI. 



Dorocidaris affinis A. Ag. 



Cidaris affinis Philippi, 1845. Arch. f. Naturg. Eilfter Jahrg. Bd. I, p. 351. 



Dorocidaris affinis A. Ag., 1869. Bull. M. C. Z., I, pp. 17 and 254; Kev. Ech. PL I, fig. 5. 



Plate 12^ figs. 1-3. 

 Mortensen' has pointed out the characteristics distinguishing this species 

 from papillata, but he fails to realize the diversity which the pedicellariaB 

 may show. It is true that the large globiferous pedicellarise are ordinarily 

 like those of Cidaris (PI. 12'', fig. s), but occasionally they are scarcely dis- 

 tinguishable from those of Dorocidaris (PI. 12'', fig. i), while not infrequently 

 they are somewhat intermediate as the opening is not quite terminal 

 (PI. 12^ fig. 2.). 



Dorocidaris Bartletti A. Ag. 



Dorocidaris Bartletti A. Ag., 1880. Bull. INI. C. Z., VIII, 2, p. 69. 



Plate 12% figs. 6-13. 

 Of all the Cidaridoe which we have examined, none exhibit more re- 

 markable diversity in the form of the large globiferous pedicellariis than 

 does this interesting and handsome West Indian species. Although the most 

 common form (PI. 12% fig. I0)is that which Mortensen- gives as the dis- 

 tinguishing feature of his proposed genus Tretocidaris, others (PI. 12% 

 fig. 7) are quite frequent which ought to distinguish a true Cidaris, while 

 others (PI. 12% figs, 6 and 9) are quite unlike either. The pedicellaria shown 

 in PI. 12*, fig. 6, may possibly be a stage of growth of the one shown in PI. 12% 

 fig. 7, but this hardly seems probable. If one were to attempt to determine 

 the generic position of this species by the pedicellaria?, it is obvious that 

 serious difficulties would arise, nor would the presence of a "limb" on the 

 stalk be of assistance, for it is also a very variable character (PI. 12% figs, li 

 and lo). This great diversity in the pedicellariae is of special interest 

 because the primary spines of Bartletti show a greater variety of form than 

 those of any other member of the genus, and according to Mortensen's 

 view^ the pedicellarioe ought to afford more constant characters. 



1 Ingolf Exped. Echiuoidea, 1903, Tt. I, pp. 35-37. 

 » Loc. cit., p. 16. 

 ' Loc. cit., p. 15. 



