4RT. 12 HEXACTINELLID SPONGES OKADA 99 



occasionally found rough liexactins having paratangentials of nearly 

 equal length, 90,u to 115|u, long and 8/x to lO/x broad at the base, with 

 proximal and distal rays measuring 120/i to I'difi in length. 



As regards the occurrence of the abnormality of the oxyhexaster 

 of this species described by Ijima, I have met with a discoctaster in 

 these specimens that represents what seems to be a case of abnormal 

 development. This occurs occasionally in the dermal membrane of 

 both specimens. It measures T2/x in diameter with an irregularly 

 shaped central node 14/x broad, with no indications of the normal 

 principals dividing into more than 30 terminals. Each terminal 

 ends in a very small pinhead. 



Genus STAUROCALYPTUS Ijima, 1897 



STAUROCALYPTUS RUGOCRUCIATUS, new species 



Figure 13 ; Plate 6, Figure 4 



A single small specimen of this species (holotype, U.S.N.M. 

 No. 22051) was obtained from a depth of 426 fathoms off Bowers 

 Bank, Bering Sea (Station 4771). The sponge body is a pair of 

 elongated, thick-walled, pear-shaped sacs. From the base the breadth 

 increases somewhat gradually until over mid-height is reached when 

 it decreases rapidly toward the oscular opening. Tlie total height 

 is 46 mm. Near the lower parts it is irregularly shaped and bent 

 inward; the maximum breadth at mid-height is 25 mm. The 

 osculum, which is elliptical in outline, measures 5 mm by 15 mm. 

 The margin is fairly thick and simple-edged. The body wall is 

 thick, decreasing gradually from 8 mm near the base to 2 mm near 

 the oscular margin. Projecting from all parts of the outer surface 

 of the sponge are many long, robust prostalia, forming a definite 

 and distinct fringe at the oscular margin. They are more abundant 

 in the lower portion of the sponge than in the upper. Those project- 

 ing directly outward from the oscular margin measure 10 mm to 

 15 mm in length. The gastral surface is smooth and has numerous 

 evenly distributed circular openings about 0.5 mm in diameter. 

 The diactinic prostals are somewhat weaker needles of various 

 lengths. They project to a free length of 5 mm to 15 mm or more, 

 being directed on the whole obliquely and outward. The pentactinic 

 prostals are of a moderately large size, and may form a gossamer- 

 like covering over the dermal surface. They generally protrude 

 in groups of two or more, but sometimes stand out singly. 



Spiculaf ion.— The prostal diactins, which are primarily to be re- 

 garded as enormously developed parenchymal principalia, are of 

 various sizes. A small one may measure 10 mm in length, while the 

 larger measure 35 mm long and 170/x thick at the middle. These 



