63 



XT. — On three species of Sponge containing some new Forms of 

 Organization. By James Scott Bowerbank, F.G.S., &c. 



Read November 24, 1841, 



In the course of the last session of the Microscopical Society, I 

 had the honor of reading a paper descriptive of the occurrence of 

 siliceous spicula in the keratose sponges of commerce, in which they 

 had not before been supposed to exist. I also described, in the same 

 paper, the existence of a vascular system surrounding the fibres of 

 certain sponges of the same class, and other peculiarities of struc- 

 ture, which I trust will have an influence in determining the true po- 

 sition which these singular creatures occupy in the animal kingdom, 

 and in some measure assist future observers in dividing them into 

 such natural groups as may render them easily recognized by the stu- 

 dent. Hitherto the modes of arrangement resorted to by naturalists 

 have been anything but satisfactory, from the distinctive characters 

 being taken, almost entirely, from their external form, and the aspect 

 and condition of their skeletons in the dry state. Such a mode of 

 proceeding is evidently insufficient for the attainment of a correct 

 knowledge of species, and among these animals especially, whose 

 anatomical details require the application of the highest microscopi- 

 cal powers that even at this period are at our command, before we can 

 attain a correct and satisfactory idea of their minute and complicated 

 structures. The classification and mutual relation of the species of 

 the higher orders of animals, have long been determined by the pecu- 

 liarities and coincidence of their anatomical structure ; and until the 

 same principles are systematically extended to the obscure and diffi- 

 cult tribe of the Spongiadae, I am convinced it will be in vain to ex- 

 pect such a classification of these protean forms as will admit of 

 their being recognized and studied by naturalists with the same degree 

 of facility that obtains in other branches of Natural History. It is 

 with the hope therefore of contributing something towards the attain- 

 ment of this desirable end, that I again introduce the Spongiadae to 

 the Society, for the purpose of describing some peculiarities in the 

 structure of three species that have escaped the observation of pre- 

 vious writers on these subjects. 



The first of these is a native of our own seas, and has not I believe 

 been hitherto described by any author. In the present state of ar- 

 rangement of the British sponges, as published by Dr. Fleming in 



