194 PHOEIOSPONGIA. 



in the surface, where they form small groups ; they are, according to Marshall 

 (loc. cit.), 0-04 millim. wide. Slender canals lead down from them to the sub- 

 dermal cavities penetrating the sand-cortex. The subdermal cavities, which 

 undermine it, are 0-2-0-3 millim. wide, and appear in the shape of irregular 

 tangential canals. At intervals of about 1-5 millim., inhalant trunks, 0'3 

 millim. wide with annular strictures, arise from them ; these are irregularly 

 curved and follow in their course the centres of the meshes formed by the 

 arenaceous bands. Small inhalant branch-canals, which are about 0*09 millim. 

 wide, radiate from them ; also in these, annular strictures are observed. The 

 ciliated chambers are oval, nearly 0-1 millim. long, and about 0-06 millim. 

 broad ; they open with very wide apertures into the smooth-walled exhalant 

 branch-canals, about 0-08 millim. wide, which lead into the tortuous oscular 

 tube ; transverse membranes are often observed in it. 



Geogeaphical Disteibution. — South coast of Australia: Bass Straits 

 {Marshall). East coast of Australia : Port Jackson, N. S. "W. {Lendenfeld). 



Phoriospongia lamella, n. sp. 



Erect, lamellar, generally irregularly flabelliform sponges, attached by a 

 narrow base. The lamella is uniformly 10-15 millim. thick, and more or less 

 curved. Specimens in which the lamella is radially folded are not infrequent, 

 but more often the lamella is simple. The free margin is rounded, continuous, 

 undulating, or lobose. In large specimens often secondary lamellae are 

 observed growing out from the primary one. Pedunculate specimens with 

 perfectly continuous free margin occur but rarely, and have only been obtained 

 at Broughton Island. The whole sponge attains a height of about 100 millim. 

 and a breadth of 220 millim. The surface is perfectly smooth and shiny in 

 the living sponge, and also in spirit-specimens ; in dry specimens it appears 

 rather granular or wrinkled. Oscula are very conspicuous and prominent, 

 2-4 millim. wide, scattered over one face of the lamella in some specimens 

 and absent in others. I establish two varieties for these accordingly, which, 

 however, differ in no other respect from each other than in this. 



The colour of the living sponge is greyish pink on the surface, dull grey in 

 the interior. Spirit-specimens are grey, but occasionally they retain a slight 

 pinkish hue. Dry specimens are light brownish grey — the colour depending 

 on the nature of the foreign bodies which form the skeleton. In the living 

 state and in spirit the sponge is pretty tough, but inflexible ; it can easdy be 

 broken. Dry specimens are more or less friable. 



The skeleton consists of isolated sand-grains, 0*4-0'8 miUim. in size, which 

 form single interrupted series, which anastomose to an irregular network 

 with rounded meshes about 1 millim. wide. The surface is protected by a 



