CHiETODIADEMA PALLIDUM. 129 



margin is coarsely dentate. The most characteristic feature is the very 

 conspicuous apophysis, which is nearly twice as high as the depth of the 

 basal part of the pedicellaria and is abruptly truncate at the end. Sucli 

 an apophysis is quite unique and it is unfortunate that the slender tridendate 

 pedicellarioB appear to be so exceedingly rare. 



The triphyllous pedicellarite are infrequent, but occur here and there, more 

 particularly on the ambulacra. They are very small, and of simple structure. 

 The valves (PI. 50, fig. 18) are .15-. 20 mm. in length, while the stalks are five 

 or six times as long. The blade is oval, rounded at the tip and without 

 any trace of a cover-plate. 



The calcareous particles in the pedicels are very infrequent, but are 

 somewhat more plentiful in the gills (PI. 50, fig. 19). They are not ])eculiar, 

 except for their small size, and usually show their triradiate origin very 

 plainly, though some of the plates may have seven or eight perforations. 



The sphoeridia are much more common than in the other species of the 

 genus, for there may be as many as sixteen in an ambulacrum. They do not 

 occur near the peristome, but are first found about three-fifths of the distance 

 from that point to the ambitus. In all cases they are found at or near the 

 ambitus, and not infrequently they are placed on the abactinal surface. 

 They are nearly globular and of moderate size, about .30 mm. in diameter. 

 They are placed in very evident depressions or hollows in the test, and are 

 distinctly pendent from the upper side of the hollow. 



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



Station 3856. Pailolo Channel, between Maui and Molokai, Hawaiian 

 Islands. Bott. temp. 66.5°. 127 fathoms. Fne. s. yl. m. 



Station 3857. Pailolo Channel, between Maui and Molokai, 11. I. Bott. 

 temp. 62.5°. 127-128 fathoms. Fne. s. yl. m. 



Station 3957. Vicinity of Laysan Island, H. I. Bott. temp. 53.5°. 173- 

 220 fathoms. Fne. wh. s. 



Station 4103. Pailolo Channel, between Maui and Molokai, H. I. Bott. 

 temp. 61.7°. 132-141 fathoms. Fne. gy. s. 



Station 4104. Pailolo Channel, between Maui and Molokai, H. I. Bott. 

 temp. 60.8°. 123-141 fathoms. Fne. gy. s. for. 



Bathymetrical range, 123-220 fathoms. Extremes of temperature, 66.5°- 

 53.5°. 



Eighty-two specimens. 



