300 AKT. 7. 1. IJIMA : HEXACTINELLIDA, IV. 



lit'xactiiiüHu luriiiH iiut fouiul. Discoctaster, 114-128/-«; found in 

 subgastral region only. Microcliöcoliexaster, 2o-26 !'■ dia. ; rare. 



;V. ffluber Ij. — Saccular or vase-like ; tliiek-walled ; some- 

 what laterally compressed after attaining a certain size. Small 

 young specimens with tine long prostal needles which seem how- 

 ever to Ijccome lost with growth. Pentactinic prostalia, never 

 present ; so that old specimens have a quite smooth external 

 surface. The extensive subdermal space and large canals give a 

 cavernous appearance to the delicatel}^ textured wall. Dermalia, 

 nearly all stauractins with microtubercles most strongly developed 

 on the outer side of the rays. Gastralia, moderately large 

 oxyhexactins, generally with the free proximal ray longer and 

 more rough than the others. Oxyhexasters, 08-114/-« in diameter ; 

 all normally developed, having 2-4 terminals to a princi])al. 

 Discoctasters may be of an unusually large size ; 240-060 !>■ in 

 diameter. Micrcxliscohexasters, 1Ö-22 i>- diameter ; not unconnnon, 

 but sometimes extremely rare. 



S. hrtei'futt lints fj. — Laterally compressed, pouch-like, with 

 narrow canals. No prostalia of any kind. Dermalia, predomi- 

 nantly stauractins, occasionally pentactins and tauactins, rarely 

 diactins ; with slightly rough rays. Gastralia, similarly rayed but 

 smaller pentactins and stauractins ; not forming a continuous 

 lacework. ( )xyliexasters, always normally develo})ed ; 100-114/^ 

 in diameter. Discoctasters, 1 1 ( )-2( )0 /'• in diameter. Microdisco- 

 hexasters, lO-lO/-« in diameter ; common in certain parts. 



S. ithofhd indes Jj. — Thick-wjdled, pear-shaped, attachetl by 

 the narrower end. With .strong ])rostal needles and a gossamer- 



