222 



Those in the Belfast museum had either been submitted to Dr. Johnson 

 or to Dr. Bowerbank ; and in quoting such species I have referred to 

 them as such ; again, several species have been named for the first time 

 by Dr. Bowerbank from specimens forwarded to him by Professor 

 Dickie, and these I give on the very excellent authority of Dr. B wer- 

 bank. The total number of species thus enumerated amounts tofifty- 

 three, or a little more than one-fourth of those described as British; but 

 I doubt not that the collection still in mypossession will enable me, 

 ere long, to double this number ; and there is no reason why the number 

 of species of sponges on our coast should be less than that of Great Bri- 

 tain. At present we have representatives of almost all the British 

 genera. 



While regarding Dr. Bowerbank' s monograph as the text-book for the 

 British sponges, I have still thought it advisable to add here and there a 

 few synonyms. Dr. Bowerbank divides the sponges into three Orders — 

 1. Calcarea, 2. Silicea, and 3. Keratosa. For facility of reference to the 

 monograph on sponges I have followed this arrangement, referring the 

 student to Professor Oscar Schmidt's work, to Dr. J. E. Gray's " Notes on 

 the arrangement of Sponges," and to Professor "Wyville Thomson's paper 

 " On Vitreous Sponges," for further information on the subject, as well 

 as for some criticisms on the arrangement of Dr. Bowerbank. The order 

 Corticataa for the Barked sponges appears to me to be a very natural one. 

 So is that of Halisarcinse for Halisarca, this genus being destitute of 

 spicules, while the Keratosa of Bowerbank, equalling the Spongina of 

 Lieberkiihn, will probably rank as an order equivalent to that of Corti- 

 cate ; but doubtless many classifications will be made and then become 

 obsolete ere a satisfactory one be established for this group of animals. 



BIBLIOGRAPHY OF WORKS REFERRING TO BRITISH SPECIES. 



George Johnston. — A History of British Sponges. Edinburgh, 1842. 

 Oscar Schmidt. — Die Spongien des Adriatischen Meeres. Leipzig, 1862. 

 ,, ,, Supplement, enthaltend die Histiologie und System a- 



tische Erganzungen. Leipzig, 1864. 

 ,, Zweites Supplement enthaltend die Yergleichung der 



Adriatischen und Britischen Spongien Gattungen. 

 Leipzig, 1866. 



J. S. Bowerbank.— A Monograph of the British Spongiadae. Vol. I. 



1864 ; Vol. II., 1866. Eay Society. 



J. E. Gray. — Notes on the Arrangement of Sponges, with the Descrip- 

 tion of some new Genera. f< Proc. Zool. Soc, London." 

 May 9, 1867. 



Wyville Thomson. — On the " Vitreous Sponges." " Ann. and Mag. of 

 Nat. Hist.," February, 1868. 



