E. OKINOSEANA. — YOUNG SPECIMENS. 241 



exclusively pentactins, not liexactins as in all mature Euplectellids. 

 The paratangential cross measures 275-650 /^ in axial length and 

 is generally slightly arched in conformity with the curvature of 

 the surface (PI. VII, fig. 8). Its rays are tapering and termi- 

 nate in pointed or conical! y obtuse ends. Besides the usual 

 roughness of surface near the end, they show a number of ob- 

 solete tubercles throughout their entire length, except along their 

 inner side where the tubercles are nearly or quite absent. 

 Generally but not always, the center of the paratangential cross 

 exhibits on the outer side a gentle swelling. The unpaired prox- 

 imal ray is developed to a length that usually exceeds by twice 

 or even thrice that of the paratangentials. Like these, it is 

 obsoletely rough ; but the roughness gradually loses itself proximad 

 towards the finely pointed end of the ray. — Seen on the dermal 

 surface, the paratangential crosses are rather irregularly disposed 

 to one another or show a tendency to arrange themselves into 

 a quadrate-meshed latticework (PI. VII, fig. 10). Sections of the 

 wall show that the elongated proximal ray reaches with its inner 

 end nearly or quite to the gastral surface (PI. VII, fig. 11). 



Ko special gastralia are present. Along the gastral surface 

 as well as in the deep part of the wall, there occur fine paren- 

 chymal diactins, mostly arranged in obliquely running and 

 intersecting strands. In some of the specimens was observed the 

 spinose microxyhexactin in isolated occurrence, while in others 

 this kind of intermedial spicule seemed to be as yet not at all 

 developed. 



Much more constant and common is the grajDhiocome. De- 

 tached sheaves of rhaphidial terminals, 170/^ and more in 

 length, are to be seen in abundance in the periphery of the 

 wall. The central relics of the graphiocome were also seen in 



