STAUROCALYPTUS AFFINIS. 185 



certain points of difference shown by several of their spicules, 

 that seem to warrant the separation of S. affinis as a distinct 

 species. 



Spiculation. 



The following description applies to the first specimen (S. C. 

 M. Xo. 194 ; PI. XIII.), unless the other specimen (S. G. M. 

 No. 400 ; PI. XIV., fig. 14) is explicitly referred to. 



The principal ijarenchymaUa are oxydiactins of unusually 

 large dimensions, often 35mm. or more in length and GOO/-« in 

 thickness in the middle. (A portion of one is seen in PI. XIII., 

 fig. 12). They occur in great abundance, especially in the 

 periphery of the choanosome. They are entirely smooth, tapering 

 gradually towards both finely attenuated and sharply pointed ends. 

 They are slightly wavy or else are bent either in a bow-like or 

 in a boomerang-like manner. Diactins of gradationally intermedi- 

 ate shape and dimensions lead over the principalia to filamentous 

 comitalia of only 12 /^ or less in thickness. 



In the second and smaller specimen the principalia attain 

 a length of 25 mm. and a breadth of 520/^. — It may be remarked 

 that in no other Staurocalyptus species are the parench^^mal 

 elements known to develop such length and coarseness. — The 

 needle-like prostal oxydiactins which were found only in the 

 second specimen may be 40 mm. long and 180 ,« thick. 



The diactins which join in the formation of hypoäermal 

 strands are mostly short, having a length of 1-2 mm. and a 

 breadth of 14-33 /i at the middle, where they may show a slight 

 annular swelling. The ends are rough, somewhat tapering and 

 obtusely or conically pointed, — not swollen as in the much longer 



