422 N. ANNANDALE, D. SC. FRESHWATER SPONGE FROM NEW GUINEA. 



marked in any spicule I hâve seen as it was in the one figured by von Lendenfeld in 

 fig. 10, pi. VI of the work cited above under his name. 



There- are no gemmules in the spécimens from New Guinea, but, as is often the case 

 in Indian spécimens of Ephydatia taken during the summer months, there are birotulate 

 spicules scattered in the parenchyma. Thèse are by no means numerous and perhaps are 

 not quite mature, but they agrée in most respects with the gemmule spicules figured by 

 von Lendenfeld. The most characteristic feature is the strong radiating ridges developed 

 on the outer surface of the solid part of each rotule. Thèse ridges are due to the fact that 

 the spines of the rotule are webbed at the base but actually spring straight from the shaft, 

 appearing on the solid part of the rotule as eminences rising above the depressed web. The 

 shafts of the birotulate spicules are fairly stout and much larger than the rotules are wide; 

 they are more or less profusely spined, generally more so than is the case in the one figured 

 by von LENDENFELD. The actual measurements of thèse spicules are on an average as follows : 



Total length 0.05 mm. 



Transverse diameter of rotule 0.023 mm. 



Transverse diameter of shaft 0.008 mm. 



The birotulate spicules are, therefore, somewhat longer than those in von LENDENFELD's 

 spécimens and hâve proportionately narrower rotules. The spines on the shaft are also as a 

 rule more numerous, more irregular and longer, often extending outwards as far as the circum- 

 ference of the rotules. Considering the variation that is known to occur in some species of 

 the genus Ephydatia, however, thèse différences do not appear to be of much importance. 



The typical Ephydatia ramsayi has been recorded from New South Wales, and 

 Weltner (1900) mentions local forms from Argentina and Paraguay. 



^ 



Spicules of Ephydatia 



from New Guinea. 



