LANUGINELLA PUPA. 11 



breadth of rays near the central node The surface is uneven 

 on account of obsolete niicrotubercies. The freely projecting rav 

 is in no way differently characterized from all the rest. The 

 gastralia occur abundantly but do not form a continuous lattice- 

 work. Oxyhexactins of precisely the same appearance also occur 

 in scattered distribution along the inner surface of excurrent 

 canals — especially of the larger excurrent canals — as the canalaria. 

 (See f]g. 9). 



The kexasters consist of the discohexaster and the strobilo- 

 plumicome. 



The discohexaster (PI. I., figs. 11 and 12 ; also Contrib. III., 

 PI. v., figs. 1-6) occurs commonly throughout the entire sponge- 

 wall. It shows considerable variations in both size and appear- 

 ance in the same as well as in different specimens. In general 

 it may l)e said to be spherical or approximately spherical, in that 

 the terminals so diverge peripherally that all the terminal discs 

 are situated neai-lv equidistant from one another. In general 

 appearance it most closely resembles certain discohexasters of 

 Chaunopleclella and of Leucopsacus scoliodocus. Tiie diameter 

 ranges from 40 /< to \)() r- (according to F. E. Schulz f, 132-100 

 /'-). In some s])ecimens of the species, however, the largest 

 discohexaster does not exceed 70 ,"- in diameter. Aside from 

 certain exceptional cases, each short or very short principal bears 

 2-4 or .") (most commonly 3) terminals. The number may vary 

 with (liH'erent principals in one and the same rosette. The ter- 

 minals ai)pear to l)e rather strong — at any rate not quite thin 

 except in the ease of the smallest discohexaster ; they are either 

 of about the same thickness tliroui»;hout the entire leuiith or 

 thicken slightly towards the outer end. Tlieir surface, when 



