BENIOCHALINA. — CAOOCHALINA. 83 



spimles are oxea, not very sharply pointed, slightly curved, 0'3-0-5 millim. 

 long, and 0-01-0-025 millim. thick. The largest spicules are those which form 

 the fibres of the third system, some of these protrude beyond the surface. 



Geogeaphical Disteibution. — Western Australia {Baihj). 



Reniochalina lamella, n. sp. 



The sponge consists of a flabelliform lamella, attached by a email base ; the 

 lamella is more or less folded, but always retains its flabelliform shape. The 

 oscula are numerous, scattered, small, and inconspicuous. The surface bears 

 small, slender conuli, 1-1*5 millim. high, and appears roughened by project- 

 ing spicules. 



The skeleton consists of three systems of fibres — one longitudinal extending 

 from the base to the margin of the lamellae, the second transverse, and the 

 third perpendicular to the surface of the lamella. The fibres belonging to 

 the first two systems accordingly extend in the direction of the lamella, 

 whilst those belonging to the third system are perpendicular to it; these 

 fibres consist of bundles of somewhat irregularly disposed spicules. The 

 meshes between the fibres are square and on an average 0*2 millim. 

 wide, the fibres themselves are 0-045 millim. thick. The spicules are 

 very A^ariable. The prevalent form is a straight oxystrongylus, with some- 

 what blunt points. Besides this, oxea and styli are found ; some of the 

 spicules are curved. Their size varies, like their shape, very much ; the largest 

 in the interior attain a length of 0*3 millim. and a thickness of 0-012 millim., 

 and those which project beyond the surface a length of 0-35 millim. and a 

 thickness of 0-0014 millim. 



Geogeaphioal Disteibution. — East coast of Australia (Ramsay). 



Subfamilia CHALININ.a:. 



Homorrhaphidse with distinct horn-fibre, in which the spicules 

 are embedded. 



Group CACOCHALININ.E. 



Chalininse of massive irregular shape, with thin fibres and slender 

 spicules. 



Genus CACOCHALINA. 



Massive Cacochalininse with very wide meshes in the skeleton- 



g2 



