214 ESPEEELLA. MTXILLA. 



millim. long. The palmate extension on one end is about two thirds as long 

 as that at the other. These chelae are mostly situated in groups 20 or more 

 together ; the ends with the smaller palmate extension of all the chelae of one 

 group are attached to each other, so that the chelae radiate from a common 

 centre, forming spherical clusters. 



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

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



Subfamilia ECTYONIN.ffi. 

 Fibres echinated by laterally projecting spicules. 



Genus MYXILLA. 



Desmacidoiiidse the magasclera of which are usually spined 

 styli ; with comparatively little spougin in the fibres. Micro- 

 sclera : tridentate chelae. 



Myxilla jacksoniana, u. sp. 



Massive, lobose sponges with conspicuous oscula. 



The skeleton consists of a very regular network of single spicules, which only 

 here and there combine to form loose and irregular bundles of two or more 

 series of spicules. The supporting spicules are styli, slightly curved, sharp, 

 and abruptly pointed at one end, and very slightly thickened at the other; 

 they attain a length of 0-2 millim. and a thickness of 0-007 millim. Besides 

 these also a few tylota are found, which, however, are very scarce; these are 

 0-2 millim. long and 0*004 millim. thick. Their ends are very slightly 

 thickened, some of them might in fact be regarded as strongyla. Microsclera 

 arev ery abundant throughout the whole of the sponge ; these are sigmata 

 and chelae. The sigmata are pi'evalent and have very abruptly I'ecurved 

 pointed ends ; they are on an average 0-04 millim. long and 0*002 millim. 

 thick. The chelaB are about a third as large as the sigmata. 



Geographical Distribution. — East coast of Australia : Port Jackson 

 N. S.W. {Juimsaij). 



