AKT. 12 



HEXACTINELLID SPONGES OKADA 



103 



Genus RHABDOCALYPTUS F. E. Schulze, 1886 



RHABDOCALYPTUS BOREALIS, new species 



Figure 14; Plate 6, Figuke 3 



As can be seen, this species has passed through my hands in no 

 small numbers. With one exception, all were obtained from the same 

 station. Some were not well preserved, the oscular margin and 

 other parts being damaged. Though these specimens all differ in 

 external appearance, they do show an essential or almost complete 

 agreement in spiculation. 



Table 22. — Record of specimens of Rhabdocalyptus borealis 



Specimen A represents a belt-purselike form, totally closed at 

 the entire lower end and lacking a special attachment of the entire 

 stock. The specimen is not well preserved, being somewhat dilapi- 

 dated in parts on the oscular edge. It is expanded outward, all 

 around, and is bent backward. The major and minor diameters of 

 the osculum are 70 mm (exclusive of the flaring rim of about 15 mm 

 in breadth and measured on the inner margin of the osculum). The 

 thin oscular edge is of a finely granular or densely feltlike appear- 

 ance. The height is 75 mm. The broadest part measures 90 mm 

 and is located below the middle of the sponge body. The wall is 

 1 mm thick in the middle of the body; lower down it is as much 

 as 1.5 mm tJtiick, and at the margin of the oscular rim as little as 

 0.8 mm. 



Specimen B is very different. It represents a vaselike, or fun- 

 nellike, form; total height, 145 mm; size of the oval-shaped o.sculum, 

 55 mm ; breadth of body, 50 mm near the upper end, near the middle 

 42 mm, and farther below 30 mm. The narrowest part of the entire 

 stock — the basal region — measures only 22 mm from side to side. 

 The thickness of the wall at the middle of the body is 2.5 mm ; far- 

 ther below, near the base of the body, it is 2 mm. The wall gradu- 



