460 " THETIS " SCIENTIFIC RESULTS. 



larger, and about 100 mm. in its smaller diameter. The peduncle 

 is 75 mm. long and from 7 to 10 mm. in diameter. Megascleres 

 oxea 0-1 mm. by 0-0065 mm. 



ARENOCHALINA, Lendenfeld. 



ARENOCHALINA MIRABILIS, Lendenfeld. 



Arenochalina mirabilis, Lendenfeld, Zool. Jahrb., ii., 1887, p. 821, 

 pi. XX., fig. 70; Id., Aust. Mus. Cat., xiii., Sponges, 1888, 

 p. 103; Whitelegge, Rec. Austr. Mus., iv., No. 2, 1901, p. 76, 

 and No. 5, 1902, p. 213. 



Station 50. 



Five examples of this species were obtained at the above- 

 mentioned station ; all wei"e evidently dead when caught in the 

 trawl. One exhibits a little sarcode, but it does not reveal any 

 additional characters to those already described. The stylote 

 spicules of the tibres and choanosome have been carefully 

 measured, and are as follows: — 015 to 0'19 by 0-004 to 

 0-0045 mm. 



CERAOCHALTNA, Keller. 



CERAOCHALINA LEVIS, Lendenfeld. 



Ceraochalina levis, Lendenfeld, Zool. Jahrb., ii., 1887, p. 782, 

 pi. xix., fig. 19. 



Sponge with a well defined base and short peduncle, 35 mm. long 

 and 15 mm. in its shorter and 30 mm. in its greater diameter. The 

 peduncle gives rise to a series of angular or compressed primary 

 branches without any anastomozation, about one-third of which 

 consists of short subcylindrical branches with round apices; their 

 length is about 150 or 200 mm. and their diameter 10 to 3 2 mm. 

 The remaining two-thirds of the branches are from 400 to 550 mm. 

 in length, subcylindrical, and about 10 mm. in diameter. The 

 longer branches exhibit two or three bifurcations. Dermal 

 surface smooth in appearance to the unaided eye, but harsh to 

 the touch. Pores minute, scarcel}' visible without a lens. 

 Yents numerous, with thin elevated margins, pretty evenly 

 distributed, 2 mm. or less in diameter, and on an average about 

 8 mm. apart. Colour in the dried condition yellowish-stone". 



Skeleton rather wide-meshed, the main fibres curve gracefully 

 from the centre outwards and terminate in small tufts of spicules 

 at the surface ; these tufts, with other scattered spicules, project 



