64 EAPHTEU8. — PAPILLISSA. 



other sponges, these cells are in connection with the digestive functions of 

 the sponge and take up and absorb microscopic food-particles, which may get 

 into the lacunae of the inhalant system and there come in contact with the 

 epithelium. 



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

 N. S. W. (Ramsay). 



Genus PAPILLISSA, n. gen. 



Very lacunar Spirastrellidae, with tubercular papillae on the 

 surface. The septa between the lacunae are so much reduced in 

 thickness as to attain a membranous character. Long and slender 

 spined oxea form the bulk of the microsclera. 



Papillissa lutea^ n. sp. 



Massive, irregular, laterally expanded sponges, attaining a width of 120 

 millim. and a height of 80 millim., attached by a small base. The surface is 

 covered with round papillfc ; these are on an average 8 millim. apart, at the 

 base 4 millim. broad, and raised 1 millim. above the depressions between 

 them. There are numerous circular, 4 millim. wide, vents scattered irregularly 

 over the surface. Colour in the living state bright yellow ; in spirit yellowish 

 white. The vents mentioned above are not true oscula, they lead into a 

 system of vestibular lacunae which occupies the interior of the sponge ; these 

 lacunae have an average diameter of 4 millim., and communicate with each 

 other by large apertures. The canal-system proper is very simple ; the 

 canals are narrow, and the tissue very dense. 



SJceleton. — The supporting-skeleton consists of dense masses of rather irre- 

 gularly disposed tylostylote Megasclera, which measure 0'6 x 0-012 millim. ; they 

 are straight or slightly curved and sharp-pointed at one end ; the bulb is 

 generally spherical, and situated either terminally or a little within the 

 truncate end ; it measures 0-024 millim. in diameter, and its usually spherical 

 shape is subject to great variations ; when the bulb is situated otherwise than 

 terminally, the spicule attains the shape of a sword. There are three kinds of 

 Microsclera: — (1) Spined strongyla, straight or slightly curved, 0-08x0-008 

 millim., with numerous short spines ; very rare. (2) Very small curved 

 spicules, 0-024 x 0-003 millim., with two regular undulating curves in them. 

 (3) Spined oxea, 0-2x0-004 millim., mostly slightly curved; spines numerous 

 and very small. 



Geographicax Distribution. — East coast of Australia : Port Jackson, 

 N. S. W. ( Jiamsay, Lendmfeld). 



