24 ART. 7. T. TJIMA : HEXACTINELLTDA, IV. 



Spiculation. 



Tho following description refers to the large type-specimen 

 shown in PL I., unless the other is specified. 



The imrenchymalia are exclusively diactins, of which some 

 may be distinguished by larger dimensions as the principalia. 



The ])rincvpalia are oxydiactins with smooth or but faintly 

 roughened ends ; generally bow-like and sometimes boomerang- 

 like in shape. The length may reach 12 mm. or more and the 

 thickness at the middle, 350 p-. The oxydiactinic prostalia are 

 evidently nothing else than principalia, which in a certain position 

 have grown excessively in length. A large prostal oxydiactin 

 measured was 50 mm, long and 275 n thick. Smaller prostalia 

 gradually grade over into the intraparietal principalia. 



Similarly, the latter intergrade with the finest (7 /^ thick) 

 parenchymalia occurring as comitalia. These and in fact all the 

 more slender parenchymalia are of a nearly uniform thickness 

 thoughout their length and terminate with rough- surfaced, conically 

 or obtusely pointed ends. Externally the spicular center is 

 indicated not even by an annular swelling. 



The thin strands constituting the irregularly meshed hyi^oder- 

 jiml latliceu'orh are made W]) for the greater part of diactins, 

 exactly comparable in characters to those of similar dimensions 

 in the parenchyma. One of them selected for the purpose of 

 measuring was about 2 mm. long and 23 /^ broad in the middle. 

 Though occasionally found running singly, they are usually more 

 or less combined into bundles of varying strength. 



