OCR Text |
Show 1867.] DR. J. E. GRAY ON SPONGES. 499 Subfam. 2. Subarmataz. Only one system of acuiform spicules. Subfam. 3. Tricuspidatce. With tricuspid spicules. Order II. OXYSPONGI.E. Keratose framework does not exist, or is almost completely atrophied. Subfam. 1. Tmp erf or antes. Numerous spicules support the soft portions of the sponge. Subfam. 2. P erf or antes. The spicules when developed only play a secondary part in giving a support to the soft parts. These three works describe many species of sponges, and present genera formed on very different principles and characters. The work of M M . Duchassaing and Michelotti pays much less attention to the microscopic structure of the sponge and the form of the spicules than either of the others. The characters of Professor Oscar Schmidt are best; but the number of species which he describes is small, and his system is artificially founded on a few prominent characters that could be easily tabulated. The work of Dr. Bowerbank contains a much more extended series of observations, and would be far superior to either of the others, if it were not deformed by his prolix style and the extraordinary nomenclature that he uses. Though he repeatedly says that external form is of no importance in a generic point of view, yet some of his genera, indeed the most natural ones, arise from his having been influenced by studying the forms and other peculiarities of the sponge. After many years attention to the study of sponges and their spicula, and the study of the various works published on them, especially those of Drs. Bowerbank and Oscar Schmidt, I would propose the following arrangement as bringing together the species which seem most allied, and also as facilitating the study of these very difficult and anomalous animals. The system was originally sketched out in 1840, and put aside. The works of Dr. Bowerbank and Dr. O. Schmidt and my subsequent observations have euabled me to improve it, and have confirmed me in the belief that it is an improvement on those before proposed. The spicules are organized bodies, and are doubtless the most important part of the sponge; they are sufficiently varied in form to present excellent characters for the distinction of sponges into orders, genera, and species. To properly distinguish the species of sponges it is necessary that all the kinds of spicules occurring in each species should be observed and noted. This being the case, the study of the sponges must be facilitated by their being divided into groups according to the form and structure of the spicules, subdivided according to the manner in which the various forms are combined in each species. It is much more easy to find the species characterized by these spicules when the sponges are so arranged than to have to read the descriptions of the species arranged into a few genera, as in Dr. Bowerbank's and Prof. O. Schmidt's works, to discover which of the |