26G ART. 7. — I. IJIMA : HEXACTINELLIDA, IV. 



towards the very base of the ray to which they belong. As has 

 been known from F. E. Schulze, the more basally situated barbs 

 may sometimes be so long that those of adjacent rays almost 

 unite. In a few instances I have seen some of the barbs of the 

 different rays actually in fusion, thus producing around the central 

 node a structure which bears a certain resemblance to a lychnisc. 



The total number of rays in an oxyhexaster of the second 

 variety may be twelve or even thirteen or fourteen. These evi- 

 dently represent cases of normal oxyhexasters, in which the six, 

 nearly suppressed principals are either all biterminal or are partly 

 l)iterminal and partly triterminal. On the other hand a large, 

 if not the greater, number of the oxyhexasters in question are 

 apparently hemihexactinose, leading down to the quite hexactinose 

 forms which are also numerously represented. Both the reduced 

 oxyhexasters just named are of the usual general shape and need 

 not be specially described. But I should mention that again in 

 this species I have encountered several instances of a principal 

 bearing divergently a well developed terminal and the spurious 

 rudiment of a second (PI. XX., fig. 10). The rudiment may 

 occur as a small unilateral spine even in the cases in which the 

 principal and the persistent terminal have straightened out as a 

 simple ray, not bent at the base (PI. XX., fig. 7). 



F. E. Schulze has found in some numbers peculiar oxy- 

 hexasters — reduced forms with six or less rays in all — in which 

 all or some of the rays present are spirally twisted (Chall. Rep., 

 PI. LXIV., figs. 10 and 11). A similar oxyhexaster was noticed 

 by me in Staurocalyplus pleorhaphides also (p. 229, PI. XVI., fig. 

 8). As regards the present species, certain specimens indeed were 

 found to possess the twisted oxyhexasters though sparingly, but 

 in several others I have searched for them in vain. I am there- 



