. 15 



Spicules (Fig. 34). 



The Body .y>iculi'# are of one sort : 



('/) Regular triradiates. Hays straight, very slender, parallel, Uuntly pointed, 

 140 M to 200 M long x 4 n to ZM thick. Ratio of length to thickness, 

 25 to 40. 



The Ocular .sy//<v//, x are of one sort : 



(/>) Alate triradiatcs, strongly folded. Basal ray straight, nearly parallel, 

 Uuntly pointed, 55 p. to 90 M long X 7 / to 8 M thick. Paired ravs nearly 

 straight in facial view, and twice bent when viewed parallel to the hasal 

 ray. Tapering, moderately sharply pointed, 00 /u to 140 /u lung x 8 M to 

 10 M thick. Ural angle 105 to 115. Angle of fold 110 



LEUCANDUA KI;I<;IJ>A. 

 (Plate XXVII., Fig. f,, and Plates XXIX. and XXX., Figs. 35-40.) 



There are eleven specimens of this new species in the collection. They are all liu- 

 shaped, with the oscule at the thick end (see Fig. G). The surface is smooth, pure white 

 and rather chalky in appearance. They varv in size from 10 mm. x '! mm. to 

 30 mm. x 10mm. (see Fig. 35). They are all solid to the touch, though thev varv 

 very much in texture when 'cut open. All liut one of the specimens have the oscule 

 completely closed, and its presence is only indicated externally by a slight 

 protuberance. < me specimen. 21 mm. long x 7 mm. diameter, has the oscule open. ; it 

 is 2 mm. in diameter, and is surrounded by a short spiculated membranous collar (see 

 Fig. 39). 



Tlie canal system varies considerably in the different specimens ; in some there is 

 a wide gastral cavity with large branching canals opening into it, while in others there 

 is no gastral canty, the excurrent canals all converging to the oscule. In cross-section 

 the specimens differ less than might be expected, for the gastral cavity appears to be 

 divided by delicate septa, which give the whole section a meshwork appearance even 

 when longitudinal sections show a large cavity. 



The excurrent canals are usually surrounded with a fairly distinct skeleton of 

 triradiates, among which are a few quadriradiates. 



The incurrent canal system is made up of a series of very irregular spaces leading 

 from the surface into the rather more regular longitudinal canals ; these run parallel 

 to the excurrent canals, from which they may be distinguished by their less 

 pronounced skeleton, which never contains quadriradiates. 



The bulk of the skeleton consists of regular triradiates ; the quadriiadiates round 

 the gastral cavities and excurrent canals are very constant in size. In some specimens 

 they are so rare that thev can onlv be found with great difficulty. The apical ray-, 

 which are slender and crocked, project into the canals. 



2 R 



