202 HAWAIIAN AND OTHER PACIFIC ECHINI. 



Station 4130. Off Hanamaulu, Kauai, H. I. Bott. temp. 46.1°. 283- 

 309 fathoms. Fne. gy. s. 



Station 4331. Off Hanamaulu, Kauai, H. I. Bott. temp. 43.7°. 257- 

 309 fathoms. Fne. gy. s. 



Station 4134. Off Hanamaulu, Kauai, H. I. Bott. temp. 43.3°. 225- 

 324 fathoms. Fne. co. vol. s. 



Station 4136. Off Hanamaulu, Kauai, H. I. Bott. temp. 44.2°. 294- 

 352 fathoms. Fne. co. s. 



Station 4137. Off Hanamaulu, Kauai, H. I. Bott. temp. 41°. 411- 

 476 fathoms. Co., vol. s., for., r. 



Bathymetrical range, 165-692 fathoms. Extremes of temperature, 54°- 

 38.2°. 



"Thirty-nine specimens. 



Sperosoma biseriatum Dod. 



Sperosoma biseriatum Doderlein, 1901. Zool. Ariz., XXIII, p. 20. 1906. Ech. d. deut- 



schen Tiefsee-Exp., Pis. XIX; XL, figs. 1-lh. 

 Sperosoma biseriatum Agassiz and Clark, 1907. Bull. M. C. Z., LI, p. 120. 



Western Indian Ocean ; 563 fathoms. 



Plate 65, figs. 15-30. 



The specimen which we have referred to this species differs very markedly 

 from Doderlein's type, and, taking these differences in connection with the 

 very great geographical and bathymetrical distances between the two spe- 

 cimens, we have little doubt that they are not identical. But in view of 

 the poor condition of our specimen and the fact that in certain important 

 particulars it agrees well with biseriatum, it has seemed to us better to let it 

 remain under this name, than to attempt the diagnosis of a new species 

 based upon it. 



The test is thicker and tougher than in Doderlein's specimen, and the 

 color, which is a deep violet where the epidermis is not rubbed off, is very 

 different. The pedicellariae also show some slight differences which we 

 have thought worth figuring. They are very abundant all over the test, 

 but only tridentate and triphyllous were found ; there seem to be no ophi- 

 cephalous ones. The tridentate pedicellariae (PI. 65, figs. 15, 16) have the 

 necks very short and the stalks 2-5 times as long as the head ; the valves 

 (fig. 18) are short and wide, closely in contact for practically their whole 



