550 A MONOGRAPH OF THE AUSTRALIAN SPONGES, 



I have sections where the whole mass of granules representing 

 one gland cells can be seen on their way out from the mesoderm, 

 through the Ectodermal Epithelium. In other sections again the 

 masses of granules are seen on the outer surface. 



These cells accordingly secret the slime by being converted into 

 it, like some of the cells in the milk glands of mammals. At the 

 same time this accounts for my observation made some years ago 

 (1) that the gland cells disappear after they have secreted slime 

 for some time. They are regenerated as long as there are a.iy 

 amoeboid wandering cells, but when there are no more of these 

 the production of slime must cease. 



It appears that these gland cells are being formed as an 

 emergency occurs, and need not necessarily always be present. It 

 would otherwise be surprising that F. E. Schulze and others did 

 not see them. 



Sensitive Cells. 



In the skin there are some isolated spindle-shaped cells, which I 

 am inclined to consider as nervous elements. (Plate 38, fig. 2 d) 

 They are very slender and taper downward to a fine granular 

 thread which can be traced for some distance. Remnants of a 

 Palpocil. (Plate 38, fig 2 e), were observed several times. 



Ganglia cells do not appear to be present. 



Geographical Distribution. 



East Coast of Australia, Port Jackson (Ramsay, von Lendenfeld); 

 North Coast of Australia, Torres Straits, (Macleay); Northern 

 Territory of South Australia, (Haacke.) 



Batiiymetrical Distribution. 

 40 metres. Port Jackson : shallow water? 



(1) R. von Lendenfeld. L.c. 



