SFEKOSOMA DURUM. 203 



length, and with nearly even, scarcely at all sinuate, margins ; the middle 

 of the blade is filled by an extensive calcareous mesh-work ; the valves 

 measure from .30-1.40 mm. in length, and the width at base is about two- 

 thirds as much. 



The triphyttoua pedicellarise (PL 65, fig. 17) are not peculiar, though neck 

 and stalk are both very slender; the valves (fig. 19) are very much like 

 those of S. obscurum, and are about .50 mm. in length. 



The calcareous particles in the tube-feet (PI. 65, fig. 20) are large, per- 

 forated plates, half a millimeter more or less in diameter ; the largest have 

 rough ridges and projections near the middle. No sphoeridia were found. 



The single specimen, about 175 mm. in diameter, was taken by the 

 " Albatross " at the following station : 



Station 4766. Between Atka Island and Bowers Bank, Bering Sea; 

 52° 38' N., 174° 49' W. 1766 fathoms. Character and temperature of 

 bottom not recorded. 



Sperosoma durum D6d. 



Sperosoma durum Doderlein, 1905. Zool. Anz., XXVIII, p. 621. 1906. Ech. d. deutschen 

 Tiefsee-Exp., Pis. XVIII, figa. 2, 2a; XL, figs. 4-4n. 



Western Indian Ocean ; 913 fathoms. 



In addition to the characters given on p. 195, the deep purple-red color 

 and the presence of ophicephalous pedicellarise are interesting features of 

 this species, of which only a single specimen, 112 mm. in diameter, is known. 

 The name refers to the character of the test, which is firmer and stouter than 

 in biseriatum, particularly abactinally. 



