306 HAWAIIAN AND OTHER PACIFIC ECHINI. 



brightest on the abactinal system, with the poriferous areas and the median 

 interambulacral areas, almost white. The spines are orange-red becoming 

 lighter at the tip. In the larger specimen, the colors are much less bright; the 

 test is paler and the whitish areas stand out in much less contrast. The spines 

 are darker at base, with more of a brown or purple shade in the red and the 

 whitish tips are more abrupt. 



There is little reason to doubt that this species stands very near Forbesianus, 

 but it seems to differ not only in the color, but in the tuberculation and in the 

 plating of the buccal membrane. Unfortunately no reliable specimens of 

 Forbesianus are available for comparison, so that there is much doubt as to the 

 true relation of the two species. The specimens collected by the "Siboga" 

 and identified by de Meijere as Forbesianus seem, so far as can be judged from a 

 single specimen from Station 173, to be nearer to Agassizii. Were this specimen 

 a little larger and more deeply colored it would be very difficult to distinguish 

 it from the smaller specimen of ruber. On comparing the larger specimen of 

 ruber with the figures given in the "Challenger" Report of Forbesianus, it may 

 be noted that the tuberculation of both the abactinal system and the coronal 

 plates is much less crowded in ruber, and in view of this fact and the striking 

 difference in color, it seems better to await further material before finally de- 

 ciding whether the two species are identical. 



The "Albatross" took ruber at the following stations: 



Station 4933. Off Kagoshima Gulf, Japan; 30 59' N., 130 29' 50" E. 

 Bott, temp. 56. 152 fathoms. Rky. 



Station 4967. Between Kobe and Yokohama, Japan; 33 25' 10" N., 135 

 37' 20" E. Bott, temp. 45.9. 244-253 fathoms. Br. m., s., for. 

 Two specimens. 



Prionechinus sculptus A. Ag. and Cl. 



Prionechinus sculptus A. Agassiz and Clark, 1907. Bull. M. C. Z., L, p. 243. 



Plates 93, figs. 24-26; 101, figs. 4-6. 



The large series of specimens shows so little diversity in form that the measure- 

 ments of the type-specimen will be sufficient to show the proportions of the 

 species. The test is 10 mm. in diameter and 5 mm. high, while the actinostome 

 is about 4.5 and the 'abactinal system a trifle over 4 mm. The primary spines 

 are 3-5 mm. long at the ambitus but are decidedly shorter abactinally. There 

 are 11 interambulacral and 12 ambulacral plates in each column. The test is 



