On the Siliceous Spicules of Sponges. 203 



pendent corroboration, by an acute naturalist, of the importance 

 of the groups in question ; but it will be obvious that, if we 

 follow the rules of priority, the names of Owen must be 

 adopted ; and even if we feel obliged to accept more charac- 

 teristic names (those based on intestinal characters), Bronn's 

 excellently chosen ones had already long existed, and there is 

 no obvious reason why they (if any should supersede Owen's) 

 should not be adopted. 

 Smithsonian Institution, 

 July 28, 1873. 



XXVII. — Notes on the Siliceous Spicules of Sponges, and on 

 their Division into Types. By Dr. J. E. Gray, F.R.S. 

 &c. 



The existence of spicules was mentioned by Ray, Ellis, and 

 others ; but I believe that Savigny was the first zoologist who 

 exhibited them in situ in living sponges, in Napoleon's great 

 work on Egypt — though, like many of the plates drawn by 

 Savigny in that work of imperial ostentation, confined to the 

 libraries of the few, the figures were without text, as the ob- 

 ject for which the Emperor had undertaken the work was past. 

 These figures have been greatly overlooked by zoologists, and 

 the importance of the spicules in the determination of species 

 and genera has only been more recently recognized. 



Savigny, in the plates of the work above-mentioned, which 

 he executed in 1805 to 1812, letters his plates " Eponges 

 charnues," " Eponges a piquans," and " Eponges a reseau," 

 and gives admirable figures of the spicules forming the second 

 division, and of the horny skeletons of his " Eponges a reseau." 

 The figures of the sponges are superior to any thing that has 

 been done since. These groups were afterwards regarded as 

 genera : — 1. Halisarca ; 2. Halichondria ; 3. Spongia. 



Prof. Ehrenberg names the spicules of these sponges as if 

 he were describing a perfect animal or the shell of a mollusk, 

 and gives to each kind of spicule a generic and specific name ! 

 overlooking the fact that there are several forms (and therefore 

 what he considers different genera and species) of spicules 

 in the same species of sponge. 



Dr. Bowerbank, in his paper in the l Philosophical Trans- 

 actions,' which was reprinted and forms the first part of his 

 work on British Sponges, figures a number of the different 

 forms which these spicules assume, and names them, but in 

 an irregular manner ; and some of the names are of extraordi- 

 nary length and composition. He gives different names to 



