118 ART. 7. 1. IJIMA : HEXACTINELLIDA, IV. 



in 'g8. Subsequently I liave liad the good fortune to discover a 

 second specimen in Mr. Owston's collection. 



The original type-specimen (S. C. M. No. 427) was obtained 

 by KcMA at a spot, about 572 m. ( = 313 fms.) deep, on Inside 

 Okinose by the Sengenzuka-line (W. of Döketsba). It is shown 

 in half natural size in PI. X,, fig. 1. In shape and other gene- 

 ral characters it so closely simulates Acanthascus cactiia that the 

 specimen long remained among the duplicate specimens of that 

 Hexactinellid until I chanced to examine it microscopically and 

 thus became aware of its remarkable différences in spiculation. 

 Since then I have subjected all my Acanthascus material to a 

 microscopical test in order to see if the determination was correct. 



The specimen is an elongate, moderately thick-walled sac 

 with several broad and irregular processes in the lower ])art. 

 One of these processes, which stands out most prominently to 

 one side, is to be considered in the light of a bud ; for, it opens 

 at the rounded end an independent osculum leading into a gast- 

 ral cavit}^ which is widely separate from that of the mother 

 person. The other processes clasp the branched skeleton of an 

 Isis on which the specimen grows. The coral branches also pass 

 through a thickened part on one side of the lateral wall. Height 

 of body, 147 mm. Breadth at the middle, about oQ mm. Thick- 

 ness of wall in that part, 9 mm.; thicker lower down the body. 

 The main osculum at the upper end is irregularly roundish, 

 measuring 33-40 mm. in diameter ; its margin is simple and 

 sharp-edged. It leads into a deep gastral cavity which widens 

 somewhat at the bottom and is continued obliquely below into a 

 tubular passage that finally opens outside by a small secondary 

 osculum situated on a gentle swelling near the lower end. 



A conspicuous feature of the species is presented by a inun- 



