H. B. Kirk.— On New Zealand Sponges. 289 



existence of the distal cones characteristic of Sycon, together 

 with the longitudinally-disposed cortical oxea that mark Ute, 

 has not hitherto been known. 



This sponge shows striking and beautiful colour-changes 

 at death. When living it is either white or dull-purple as a 

 rule, but in dying it turns saffron-colour, red, and bright- 

 purple. 



Localities. — Cook Strait ; Hokianga Heads. 



Lamontia, new genus. 



Grantidce with spherical or polygonal flagellated chambers ; 

 skeleton of the chamber - layer consisting entirely of oxea ; 

 dermal cortex containing radiates. 



Lamontia zona, n. sp. Plates XXV., XXVI. 



Sponge solitary; oxea of chamber-layer small and curved; 

 cortical skeleton of large 3-radiates, of small oxea like those 

 of the chamber-layer, and of large projecting oxea and oxy- 

 strongyla ; gastral armature for the most part of small 

 dagger-shaped. 4-radiates, but of large 4-radiates near the 

 oscule ; peristome of long oxea with sagittal 3-radiates at the 

 base on the inner side. A specialized pore-area is present, 

 and this area is without any projecting oxea or oxy-strongyla. 



This sponge is from 14mm. to 20mm. in height, and from 

 4mm. to 7mm. in breadth. The external armature of oxea 

 does not appear at first sight to differ from that of many 

 other leuconoid sponges, but the unarmed pore-area enables 

 the sponge to be distinguished at a glance. This area is 

 usually a little below the oscular opening, and in the best 

 specimens it forms a regular zone of a dead- white colour. 

 It may, however, in specimens more or less misshapen, be 

 irregular in outline, and may even become a longitudinal strip. 

 The groups of pores in this specialized area lead into well- 

 marked chones, below which are well-developed subcortical 

 chambers. Between the chones are columns and walls of 

 superimposed 3-radiates, which support the pore -bearing 

 membrane. The membrane contains small oxea exactly like 

 those of the chamber-layer. I believe that the existence of 

 a specialized pore-area is not known in any other calcareous 

 sponge. Pores are not confined to the specialized area, but 

 are scattered over the whole dermal surface. Beneath the 

 cortex, in other parts of the sponge than below the pore-area, 

 are subcortical lacunae of irregular shape and varying size. 



Spicules : — 



(1.) Projecting oxea of dermal cortex : Very large, thickest 

 near the proximal end, often of wavy outline ; size may be as 

 much as 09mm. x 0051mm., or even greater. 

 19 



