114 HAWAIIAN AND OTHER PACIFIC ECHINI. 



numerous perforated plates than we have found in any other species, but this 

 feature is not sufficiently constant to be relied upon for a specific character. 

 This species was taken by the " Albatross " at Acapulco, Mexico, 1905. 

 Two specimens. 



Diadema paucispinum A. Ag. 



Diadema paucispinum A. Agassiz, 18G3. Bull. M. C. Z., I, p. 19. 



Plate 51, figs. 1, 2. 



As Mortensen was unable to examine the pedicellariae of this species, we 

 have given a figure of a valve of one of the large tridentate, which shows 

 some characteristic features. It is an open question whether these pedicel- 

 lariaB should be called " slender " or " stout " tridentate, but we have pre- 

 ferred to regard them as ''slender," because the valves, though broad, are 

 distinctly compressed and are very straight. Occasionally they approach 

 in form the slender tridentate of setosiim, but the valves are never suf- 

 ficiently narrowed to make confusion with that species possible. The 

 margin of the valves is strongly dentate, and the tip is broad and bluntly 

 rounded. The calcareous network in the blade is well developed. 



This species was taken by the "Albatross" at the following stations: 



Piiako Bay, Hawaii, Hawaiian Islands. 



Honolulu, Oahu, H. I. 



Station 3968. French Frigate Shoal, H. I. 14r,-161 fathoms. Crs. s. co. 



Station 4169. Off Modu Manu, H. I. Bott. temp. 78.6°. 21-22 

 fathoms. Co. 



Nine specimens. 



Diadema Savignyi Mich. 



Diadema Savignyi Michelin, 1845. Rev. Mag. Zool., p. 15. 



It is an interesting fact that the Diadema found by the "Albatross" at 

 Easter Island should piove to be of this species, thus extending its known 

 range far to the southeastward. As there is only a single specimen, and 

 that not in good condition, we have only found one or two examples of 

 large tridentate pedicelhiri.T. These, however, agree sufticiently well with 

 those of Sarif/nf/i to warrant our calling the specimen by that name, especially 

 since the reddish color, the large abactinal system, and the beginning of the 

 second series of interambulacral tubercles on the sixth coronal plate are fea- 



