210 I. uni A : hexactinellida. i. 



tlie peculiarity referred to in the arrangement of the beams oc- 

 curred only here and there without regularity in the longitudinal 

 system, and as regards the circular beams, only in the upper 

 region of the body. My observations are in general accord with 

 Schulze's, The arrangement of the longitudinal beams is 

 exactly similar to that observed by Schulze ('95, p. 25) in 

 E. simplex and by me in E. marshalli (p. 94). The same may 

 also be said with respect to the circular system. Only I have to 

 add that the relatively close arrangement of the circular beams 

 noticed by Schulze in the upper region of the body is to be 

 observed only in the younger specimens in which that region is 

 still actively growing, and the said beams are there either under- 

 going, or have comparatively receîitly undergone, multiplication 

 by splitting. In a specimen of 138 mm. length (Spec. D), I 

 iiave found the region near the upper end still characterized in 

 the way indicated. In all the larger speciuiens, the circular 

 beams are set well apart from one another, notwithstanding the 

 occasional occurrence of anastomosis. After the specimen has 

 nearly attained full size, a number of the uppermost circular 

 beams seem to deviate from their regularly transverse course and 

 become more oblique and wavy, so that they often anastomose 

 and even intersect one another. At their juncture with the 

 sieve-plate, they are frequently seen to be prolonged, like the 

 longitudinal beams, into the beams of that plate, similarly as 

 described by me for E. marxhalli (p. 94). 



The number of skeletal beams has been counted in five 

 specimens, as follows : 



