144 Royal Society : — 



PROCEEDINGS OF LEARNED SOCIETIES. 



ROYAL SOCIETY. 



June 19, 1862. — Major -General Sabine, President, in the Chair. 



" Anatomy and Physiology of the Spongiadse." Part III. By 

 J. Scott Bowerbank, LL.D., F.R.S. 



This paper is the third part of the Anatomy and Physiology of the 

 Spongiadae. The author, after pointing out the inefficiency, or rather 

 the non-existence of a definite arrangement of species of sponges, 

 proposes to establish a series of orders, suborders, and genera, the 

 distinguishing characters of which are to be founded on the structural 

 peculiarities of the various organs of the animals which have been 

 described in detail and named in the first and second parts of the 

 paper. The term Amorphozoa, proposed by De Blainville as a 

 designation of the class, is rejected, as all sponges cannot be considered 

 as shapeless, many genera and species exhibiting much constancy in 

 their forms, while that of Porifera, proposed by Dr. Grant, is adopted, 

 as the porous mode of imbibition of nutriment is universal in this 

 class of animals. The author also agrees with Dr. Grant in dividing 

 the class into three great orders, dependent on the nature of the 

 substances of which the skeletons are constructed. These three 

 great divisions are designated by Dr. Grant in the following order : — 

 1st, Keratosa, having skeletons of horny structure, with few or no 

 siliceous spicula; 2nd, Leuconida, the skeletons composed of cal- 

 careous spicula ; and 3rd, Chalinida, the skeletons constructed of 

 siliceous spicula. The author, for reasons stated in detail in the paper, 

 proposes to change the order of this arrangement, placing the cal- 

 careous sponges first, under the designation of Calcarea. The siliceous 

 sponges are placed second, and designated Silicea, while the first 

 order of Dr. Grant, Keratosa, is placed last. With these exceptions 

 of arrangement and designation, the orders are essentially those 

 established by Prof. Grant in his " Tabular View of the primary 

 divisions of the Animal Kingdom." 



The first of these orders (Calcarida) has hitherto been repre- 

 sented by the genus Grantia only ; but as the genus as established 

 by Fleming contains sponges having very differently constructed 

 skeletons, the author has divided the whole of the species of calcareous 

 sponges that have been named and described into the four following 

 genera, Grantia, Leucolenia, Leuconia, and Leucogypsia, in accord- 

 ance with four distinct types of skeleton-structure which are found to 

 exist among the sponges originally arranged under the genus Grantia 

 of Fleming. 



The second order, Silicea, is very much more extensive than that 

 of Calcarea, and, from the striking varieties it affords in the con- 

 struction of the skeletons, it allows of a subdivision into seven sub- 

 orders. The first of these consists of sponges having spiculo-radiate 

 skeletons, and contains thirteen genera, as follows: — Geodia, Pachy~ 



