70 



ESSAY ON SPONGES. 



perfect. Those in which we are the least likely to 

 err, are such as are branched, lobated, foliated, or 

 digitated, or possess something like specific cha- 

 racters independent of texture ; but, at the same 

 time, texture must be a leading feature in discri- 

 mination, for, in the more compact sponges, desti- 

 tute of ramifications or appendages, and where 

 shape has no uniformity, texture alone must guide 

 our opinion. 



Under all the difficulties I have to encounter 

 with respect to synonyma, I am induced to offer 

 an essay on the British species of this intricate 

 genus, for these reasons : 1st, Because T possess 

 many that do not appear to have been described ; 

 2dly, Because no British naturalist, since Ellis, 

 has exclusively undertaken the subject ; and, Sdii/, 

 Because it may pave the way to greater exertions 

 in this occult science, by stimulating others to reap 

 in the same field, and give their gleanings to the 

 public. 



If I fall into error with respect to synonymes,. 

 those who have studied the subject will readily 

 excuse it, from their knowledge of the difficulty 

 of avoiding it. If I fail in my endeavours to de- 

 fine all the British species of Spongia, I am sure of 

 obtaining two desirable objects ; — that of the 

 pleasure and information the study and researches 

 have afforded me ; and also that of allowing the 

 scientific to participate with me in the benefit of 

 these researches, which some friends have urged 

 me to publish. 



