330 FUNAFUTI ATOLL. 



The fibres are pretty uniform in diameter without any well 

 defined branches. Occasionally they appear to be connected by 

 a somewhat dense bundle of spicules. The intercolumnar spaces 

 are sparsely spiculate. The spicules are rather irregularly arranged, 

 both in the spaces and the columns. There are no traces of a 

 special basal or dermal layer of spicules. 



Megasclera Of two kinds, stylote and oxeote. (a) The styli 

 are usually curved, rarely straight, often bent a short distance 

 from the well rounded base ; they taper gradually from about the 

 middle to sharp points. 



Size Variable, about 0-2 to 0-04 mm. by 0-0095 mm. 



(6.) The oxea are not so numerous as the styli, they are usually 

 bent in the middle, and taper gradually to sharp points. 

 Size About 0-35 by 0-0075. 



Besides the above, there are a number of very slender oxea 

 and styli scattered through the body, probably the young of the 

 larger forms. 



Reefs in the lagoon. 



FAMILY SUBERITID^E. 



POLYMASTIA DENDYI, Sp. nOV. 



(Plate xviii., fig. 5). 



Sponge sessile, consisting of a series of mammiform processes 

 more or less united at their bases, the upper third or half being 

 free. The single example in the collection is 35 mm. in its long 

 and 25 mm. in its short diameter, and about 8 to 12 mm. in 

 height. The mammiform processes are roundly conical, varying 

 somewhat in size; they are from 4 to 12 mm. in diameter at the 



The sponge is pretty firm, elastic, and moderately tough, the 

 surface has an appearance like velvet, due to the projecting 

 stylote spicules. 



The oscula are minute, and are situated in the centre of a 

 smooth membrane at the summits of the processes. The aperture 

 is about 0-25 mm. in diameter. The smooth membrane about 

 1*5 mm. The oscula margin is plain or but very slightly raised, 

 pores not visible. 



Colour in spirits light sandy gray. 



Skeleton composed of numerous, slender columns of spiculo- 

 fibre running vertically towards the surface, where they terminate 

 in tufts of diverging spicules which project a considerable distance 

 beyond the dermal layer, and give the surface the characteristic 

 velvety appearance. The dense dermal layer of small spicules is 

 about 0'3 mm. in thickness ; they are somewhat irregularly dis- 



