DYSIDEOPSIS, lo5 



Indian Ocean : Seychelles Islands (' Alert ') ; Grulf of Manaar ( Warren). 

 South-west coast of Australia (Bowerbank Coll.). West coast of Australia : 

 Western Australia {Baily). 



Genus DYSIDEOPSIS, n. gen. 



Spongidse with large spherical ciliated chambers 0-04-0'048 

 millim. wide, and a skeleton composed of a miiform network of 

 areniferous fibres which are not clearly distinguished into main 

 and connectina:-fibres. With conuli on the surface. 



*o 



Dysideopsis elegans, n. sp. 



Erect, branched, digitate sponges which consist of a small bunch of upright, 

 regularly cylindrical processes, 6 millim. thick, which grow out from a common 

 basal mass. The whole sponge attains a height of 120 millim. The processes 

 are distally rounded. The surface;;^ is covered with elegantly shaped conuli, 

 2-3 millim. high and 1-3 millim. apart. The slopes of the conuli are very 

 concave, arid so they appear very slender in their distal portions. The conuli 

 are connected by prominent ridges, the height of which is inversely propor- 

 tional to the distance of the conuli, which they connect. The oscula are 

 scattered, rather scarce, 1 millim. wide. 



The living sponge is very dark , brown or nearly black on the surface, and 

 dull brown in the interior. This colour is retained by spirit-s]-)ecimens. 



The skeleton consists of fibres 0-06-0-08 millim. thick, which are pretty 

 smooth, and completely filled with small sand-grains. The fibres are straight, 

 pretty sharply angularly bent at the joining points, and anastomose to form a 

 netwoi'k with irregular, more or less polygonal meshes, which are on an average 

 0-4 millim. wide. Main and connecting-fibres cannot be distinguished at alL 

 The conuli are supported by a bundle of three or four radial fibres, which 

 approximate distally and give off tangential branches. 



The subdermal system is represented by large separate tangential canals, 

 which are situated radially round the conuli, between the very stout muscular 

 bauds which radiate from them. The ciliated chambers are spherical, pear- 

 shaped, on an average 0-048 millim. wide. 



Geogeaphical Distribution. — East coast of Australia : Port Denison, Q 



{Ramsay). 



Dysideopsis digitata, n. sp. 



The sponge consists of a small bunch of short, cylindrical, slightly curved, 

 digitate processes, which are 12 milli)n. thick, and attain a length of 40 



