178 Transactions. — Zoology. 



towards the point of the apical ray. Ordinary length of basal 

 ray, 0'15mm.; of oral rays, 0"13mm.; and of apical rays, 

 0"07mm. Thickness of rays at base, 0-015mm. They taper 

 evenly to a point. The apical ray is slightly curved away 

 from the basal ray, and the point is directed towards the oscu- 

 lum of the sponge. 



Oxeotes (PI. XXII., fig. le) : Tliese are slender and at times 

 almost filiform. They generally taper irregularly to sharp 

 points at both ends. The thickest part of the spicule is gene- 

 rally near the basal end, and near this end is often a sharp 

 bend in the spicule. Sometimes the spicules are slightly 

 truncated or quill-shaped at the base. Length, 0-24mm. to 

 0"73mm. ; greatest breadth, 0-Olmm., but sometimes the 

 greatest breadth is not more than 0-005mm. 



The projecting oxeotes give this sponge a hispid appearance, 

 observable with the naked eye. The fact that although gene- 

 rally directed towards the oscule they often project at right 

 angles to the" axis of the tube, and are often directed towards 

 the sponghoriza, gives the tubes the echinated appearance 

 that suggests the specific name of the sponge. This appear- 

 ance, and the comparatively large size of the sponge, are the 

 external characters that distinguish it from L. lucasi, Dendy, 

 to which it is allied. The microscopic characters that distin- 

 guish it at once from L. hicasi are the immense size and more 

 tapering shape of its oxeotes, and the fact that its quadri- 

 radiates are for the most part noticeably larger and less regu- 

 lar than the triradiates. The triradiates are larger than those 

 of L. lucasi. 



Localities. — Cook Strait, Poverty Bay, Kawakawa (near 

 East Cape). 



In a sponge that appears to be a form of this, and that occurs 

 on Stewart Island, there is a tendency in the ascon tubes to 

 branch. The 4-radiates in this sponge are not larger than the 

 3-radiates, and are much less numerous. The oxeotes, more- 

 over, are smaller, and do not tend so decidedly to be filiform. 

 This form makes a near approach to L. lucasi. 



2. Leucosolenia lucasi, Dendy. 



Tlie following account of the sponge is slightly compressed 

 from Dr. Dendy's description : — 



Sponge forming loose colonies, the ascon persons being con- 

 nected at their base by a hollow creeping sponghoriza. Ascon 

 persons small, cylindrical, thin-walled tubes, 2mm. or 3mm. 

 in height, and 0'7mm. in diameter. When the sponge is full- 

 grown each tube has a wide osculum at the summit. Outer 

 surface of tubes minutely hispid. Colour in spirits, white. 



Skeleton of 4 -radiates, 3-radiates, and oxeotes. The 

 radiates are arranged in a single layer in the thickness of the 



