KE VISION "BRITISH SPONGIADiE. 



231 



But I have not deemed it necessary to give the generic 

 definitions in the other groups of Sponges, as for the 

 Calcarea I have exclusively followed Dendy {2, 8, 4), for 

 the Tetractinellida, Sollas (17), and for the Hexaceratina 

 and Monoceratina, von Lendenfeld (13). The definitions 

 of the genera of these groups will be found in the works 

 of these respective authors. 



