NOTES ON APHROCALLISTES BEATRIX GRAY. 



175 



tubercled throughout. This may be due in a measure to the age of the 

 sponge, as was pointed out by F. E. Schulze. The intercanalar dictyonal 

 septa, in the parts between the radial lines of their junction with one 

 another, are thin, but not quite flat and even. In them the dictyonal beams 

 do not run all in the same plane, nor always in a single regular tier as seen 

 in sections ; so that, the septa in sections present an appearance more like 

 that of a thin sheet of an irregular three-dimensional framework than of a 

 single-layered network evenly spread out. This stands somewhat at 

 variance with the evenly complanated state of the septal dictyonalia as 

 figured by F. E. Schultze ('04, pl. XI. fig. 2) from a specimen taken in 

 Siberut Strait on the SW. coast of Sumatra, or as I myself have found in 

 many of the Malayan specimens collected by the Siboga. The dictyonal 

 nodes are but slightly or not at all swollen. 



The rough spikes growing out from both dermal and gastral edges of 

 intercanalar septa vary much in their development according to individuals. 

 Spikes on the surface of the septa are of but exceptional occurrence, — 

 another fact which seems to be noteworthy in view of their apparently 

 frequent and numerous presence in that position — all pointed towards the 

 external opening of the canals — in Malayan as well as Indoceanic 

 specimens. 



Free oxyhexactins occur in very varying numbers. In the oriental 

 form I find them to fluctuate from 50/i to loorx in length of rays. The rays 

 are rough, but scarcely ever distinctly spiny. 



The uncinates offer no important points of characterization which might 

 likely be utilized for the differential purpose within the species. The same 

 may be said of the rough diactine gastralia (up to 1.4 mm. long in the 

 oriental form). 



The dermalia exhibit some points which seem worth while to call 

 attention to. In the oriental form they are both pentactins and hexactins, 

 of which the latter have the distal ray in various stages of development to- 

 wards acquiring a plumose character (hexactine pinules). In some of the 

 specimens the hexactine dermalia are decidedly rare, while in others they 



