50 TETHTA, 



irregularly from all parts of the surface ; they are not very numerous, and 

 generally arranged in groups or zones, leaving portions of the surface without 

 appendages. The cortex of spirit-specimens is of a light flesh-colour, the 

 interior dirty yellow. The cortex is in the free part of the sponge 3 milliin., at 

 the base only 1 millim. thick. Oblique, up to 0-16 millim. wide, canals are met 

 with in the cortex, which join to form tangentially extended subdermal cavities. 

 The inhalant stems extend centripetally down from these, pervading the 

 cortex ; they are widened in a trumpet-shaped manner at each end, and at 

 the narrowest portion 0*08 millim. wide. The usual radiating canals are 

 found in the interior. 



Skeleton. — The centre from which the bundles radiate is situated in the 

 middle of the base ; the bundles have a thickness of 0*5 millim. There are 

 two kinds of stellate microsclera, which are particularly abundant in the 

 skin. — (1) Megaschra. Styli 2x0-014 millim,, cylindrical and straight, 

 sharp-pointed, the pointed end looking outward. In the cortex smaller 

 spicules of a similar kind are met with ; these are often curved, and 

 measure 0*6x0'07 millim. — (2) Stellate Microsclera. Of two kinds: — (A) 

 Larger stellates, with conic, pointed rays, sparsely scattered throughout the 

 body of the sponge, measuring 0"05 millim. in diameter. (B) Small stellates, 

 with slender, cylindrical rays, terminally thickened, forming a dense outer 

 coating on the surface, and present also in the walls of the inhalant canals, 

 measuring 0*012 millim. in diameter. 



Geographical Distributiotst. — East coast of Australia : Port Jackson, 

 N. S. W. (Bamsay, Lendenfeld). 



Tethya phillipensis, n. sp. 



Spherical or kidney-shaped sponges, generally broader than high, measuring 

 20-35 X 15-20 millim. ; attached by a small portion of the base only. The 

 kidney-shaped specimens are always attached at the indenture. Sometimes 

 thick and short, root-like appendages are developed. Surface tuberculated, 

 divided by reticulate depressions into polygonal areas, which measure on an 

 average 2 millim. in diameter, and are raised 0-5 millim. over the surface. By 

 a perforation of the membrane, which extends between the projecting tubercles, 

 a structure is produced which strougly resembles the rosettes of Tethya 

 Jissurata, above described. In the living state and in well-preserved spirit- 

 specimens the cortex and portions of the pulpa are light red, flesh-coloured, 

 the remainder of the sponge is colourless. The cortex is 2-3 millim. thick ; 

 at the lower limit of the cortex, irregular tangential canals, with an average 

 diameter of 0-4 millim., are met with ; very narrow radial canals extend 

 down from these. 



