110 ART. 1. — I. IJIMA : HEXACTINELLIDA, III. 



LEUCOPSACID^: Ij. n. fam. 



Lyssacine Hexasteropliora of tllick-^Yalled, cup-like 

 or ovoid body; sometimes stalked; firmly attached by 

 base (? or rooted by basal spicules). Dermal skeleton 

 composed as a rule of moderately large pentactins 

 with the unpaired ray directed proximad ; hypo- 

 dermalia not distinguishable. Hexasters represented 

 mainly by discohexasters (no oxyhexaster). 



A key to the genera and species of this new family is 

 found on p. 33. 



LEUCOPSACUS Ij. 



Ijcucopsacids with small, ovoid or spindle-like body, which 

 may be stalked. Parenchymalia chiefly hexactins ; diactinic 

 parenchymalia present, but \)]i\j a subordinate part. Gastralia 

 represented by hexactins similar to those of the parenchyma. 

 Discohexasters in part hexactinose and in part hexasterous. 



Leucopsacus oyfhodocus Ij. — Leucopsacus with the inferior 

 end of body narrowed into a stalk. Parenchymal hexactins 

 regular and straight-rayed ; forming an approximately regularly 

 quadrate-meshed framework. Besides hexactinose discohexasters 

 (110-168/^ axial length), there occur smaller hexasterous forms 

 (60-75 /^ dia.) in which the terminals to each principal form 

 a distinct bell-shaped tuft. 



Len((>iisf(cus scoUodocus Ij. — Leucopsacus without a long 



