58 SPTBASTEELLA. — PAPILLINA, 



pores downward, are oblique to the surface, 0-2 millim. long and 0-04 

 millim. "wide, and join in an irregular manner to form larger stems, 

 which occasionally attain a width of 0-5 millim. ; 1-3 millim. below the 

 surface, cyhndrical canals, with a diameter of 0-6 millim., extend in a strictly 

 tangential direction ; these are not numerous and about 4 millim. apart ; they 

 represent the subdermal cavity. The canal-system in the interior is very 

 regular ; there the canals have an average width of 0*2 millim. ; only the much 

 curved oscular tubes are wider, having a diameter of about 1 millim. ; the 

 sponge therefore appears very dense. 



Skeleton. — The skeleton consists of a dense mass of large spirastrellids 

 and small bundles of slender tylostyli. — (1) TyJostylote Megasclera. Tylostyli 

 0-6 X 0-01 millim., cylindrical, pointed at one end ; bulb terminal, spherical, 

 0*016 millim. in diameter. — (2) Spirastrellid Microsclera. Very irregular, elon- 

 gate stellates and short rods with long spines, about as frequent as the regular 

 stellates ; the different shapes appear as transition forms between the regular 

 stellates of the Tethydse and the spined rods of Papillina ; their diameter 

 averages 0-04 millim. ; their rays or spines are conic and sharp-pointed, about 

 1 i times as long as thick at the base. 



Geoqbaphical Disteibution. — East coast of Australia : Port Jackson, 

 N. S. W. {Ramsay). 



Genus PAPILLINA. 



Cavernose Spirastrellidse with tubercular papillae on the surface ; 

 microsclera, spined strongyla. 



Papillina panis, n. sp. 



(Plate I. figs. 1, 2.) 



Massive, irregular, lamellar or cup-shaped erect sponges ; the largest speci- 

 mens attain a leugth of 300 millim. and a thickness of 60 millim. at the base, 

 tapering to 20 millim. below the margin ; the sponge is always attached by 

 a broad base. The surface is covered everywhere, except in the vicinity of the 

 vents, by rounded papillae, which have the shape of segments of spheres, and 

 which are divided from each other by a network of broad and flat depressions ; 

 the papillge are from 6-9 milhm. apart, have a breadth of 2-4 millim. at the 

 base, and project 1-2 millim. above the depressions. Surface purplish brown or 

 dirty white ; interior Hght greyish brown in the liviug state ; the colour 

 remains unchanged in spirit. 



Vents, covered for the most part by movable membranes, are found on 



