102 HAWAIIAN AND OTHER PACIFIC ECHINI. 



Dermatodiadema globulosum A. Ag. 



Dermatodiadema globuloaum A. Agassiz, 1898. Bull. M. C. Z., XXXII, p. 76. 

 1904, Panamic Deep Sea Echini, PI. 24, figs. 1-3. 



Plate 50, figs. 6-10. 



Tliis species has not yet been taken outside of the Panamic region, but we 

 include it here in order to describe and figure the pedicellariae. 



The slender trideniate pedicellariae are common. In the largest ones the 

 valves (PI. 50, fig. 7) are remarkably long (about 1.65 mm.) and narrow, 

 with nearly straight margins, and meet each other for nearly their entire 

 length. Smaller ones have the valves from .50 to 1.50 mm. long and not 

 essentially different in form. 



The stout bidentate are unfortunately rare, for they are very characteristic. 

 The valves (PI. 50, fig. 6) are about 1.5 nun. long, with the base about .90 

 mm. broad, and the tip rounded. The blade is filled with a coarse network 

 and the margins are decidedly sinuate. 



The ophicephalous are not very common. The valves (PI. 50, fig. 9) are 

 very small, only .20 mm. in length, and are broadly rounded at the tip. 



The triphyllous are common everywhere and appear to intergrade with the 

 slender tridentate. The valves (PI. 50, fig. 8) are remarkably long (up to .50 

 mm.) and have the cover-plate deeply cleft. 



The spicules in the pedicels have the ends usually drawn out and imper- 

 forate .as in tonsiun, but sometimes flat and perforated. 



The spha3ridia (PI. 50, fig. 10) are large, somfewhat longer than thick. 



Dermatodiadema horridum A. Ag. 



Dermatodiadema horridum A. Agassiz, 1898. Bull. M. C. Z., XXXII, p. 76. 

 1904, Panamic Deep Sea Echini, PI. 24, figs. 4-12. 



Plate 50, figs. 11-15. 



We include this species also for the sake of the pedicellarii\?, which appear 

 to be very easily distinguished from those o{ globulosum ; so far as our limited 

 material of the latter permits us to speak, we should say the differences are 

 very constant. 



The slender tridentate are fairly common. The valves (PI. 50, fig. 12) rarely 

 exceed 1 mm. in length, and the blade is relatively broader and flatter than 

 in (jlubidosum. 



