REPORT ON THE MONAXONIDA. 



261 



have brought to light no less than 24 species of Monaxonid sponges (belonging to 14 

 genera) which live below the thousand fathom line, amongst which 13 live at depths of 

 2000 fathoms or more, as will be seen from the following list : — 



List of Species which live below the 1000 fathom line. 



Of the 14 genera thus represented, 9 {Cladorhiza, Axoniderma, Chondrocladia, 

 Meliiderma, Phakellia, Polymastia, Trichostemma , Tentorium and Stylocordyla) must 

 be regarded as characteristically belonging to the deep-sea fauna, being rarely or never 

 met with in shallow water, while the remaining j&ve are on the contrary typically 

 more or less shallow-water forms, and are rarely met with at very great depths. 



The scarcity of Monaxonid sponges at very great depths is fully compensated for by the 

 unusual interest attaching to the few species which do occur. In examining the twenty- 



