1867.] DR. J. E- GRAY ON SI'ONGES. 499 



Subfam. 2. Sulxirmafa. 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. Imp erf or antes. Numerous spicules support the soft 



portions of the sponge. 

 Subfam. 2. Perforantes. 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 diflferent prmciples and characters. The work 

 of ^IM. 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 supe- 

 rior 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 spi- 

 cula, and the study of the various works published on them, espe- 

 cially those of Drs. Bowerbank and Oscar Schmidt, 1 wo\ild propose 

 the following arrangement as bringing together tbe species which 

 seem most allied, and also as facilitating the study of these very diffi- 

 cult and anomalous animals. The system w^as originally sketched 

 out in 1840, and put aside. The works of Dr. Bowerbank and Dr. 

 O. Schmidt and my subsequent observations have enabled me to 

 improve it, and have confirmed me in the belief that it is an im- 

 provement on those before proposed. 



The spicules are organized bodies, and are doubtless the most im- 

 portant 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 iu 

 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. 

 Bowerbauk's and Prof. 0. Schmidt's works, to discover which of the 



