On the Siliceous S^ncules 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 Sjjonges, 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 :Hrst 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. Halisar-ca] 2. Ilalichondria] 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 speciis of sponge. Dr. Bowerbank, in his paper in the ' 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
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