102 HAWAIIAN AND OTHEK PACIFIC ECHINI. 



Dermatodiadema globulosum A. Ag. 



Dermatodiadema globulosum 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. 



This 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 tndeniate pedicellarice 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 stoid, tridcntate are unfortunately rare, for they are very characteristic. 

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

 mm. broad, and the tip rounded. The blade is filled wit'i a coarse network 

 and the margins are decidedly sinuate. 



The ojMcephalous 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 tonsHin, but sometimes flat and perforated. 



The sphasridia (PI. 50, fig. 10) are large, somewhat longer than thick. 



Dermatodiadema horridum A. Ag. 



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

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



Plate 50, figs. 11-15. 



We include this species also for the sake of the pedicellariae, which appear 

 to be very easily distinguished from those oi globidosum ; 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 globulosum. 



