Dr. J. E, Gray on the Classification of Sponges. 443 



general arrangement of the families, which is the result of a 

 continued study of the sponges and of the various books and 

 essays that have been written upon them. 



I have thought it well to propose this arrangement, leaving 

 the details of the genera for naturalists who are younger and 

 have better eyes than I have or am likely to have at my 

 advanced age. 



In the 'Annals and Magazine of Natural History' for 1868, 

 vol. i. p. 165, 1 did propose a revision of the arrangement of the 

 families ; but more experience in the study of these bodies has 

 induced me to suggest a further modification, retaining the 

 families suggested in the first paper, but abolishing the divi- 

 sion oi Malacosporoi and Chlamydosporce (as it is nearly certain 

 that Avhat Dr. Bowerbank calls spores or ova in Geodia have 

 nothing to do ^vith generation), though retaining the section for 

 the freshwater sponges, which have ova of very different 

 structure from that found in marine sponges. 



I believe the system I proposed in 1867 and 1868 may be 

 much simplified by leaving out some of the larger divisions, 

 though the groups separated by them are evidently natural. 

 Thus, for example, misled by the confidence I placed in Dr. 

 Bowerbank's observations, I called the spherical mass of spi- 

 cules in Geodia ovisacs, which he says become converted into 

 these balls ; but my friend Mr. Carter states, in the ' Annals 

 and Magazine of Natural History' for 1869, vol. iv. p. 17, 

 that "on no occasion have I been able to discover any central 

 cavity in any stage of their development ;" and he calls them 

 " globular crystalloids," considering them the same as the 

 large stellate bodies in Tethya^ called by Dr. Bowerbank 

 " stellate spicules," while he describes the seed-like bodies of 

 SpongiUa as commencing in a simple spherical soft cell, look- 

 ing like a white speck imbedded in the sponge, and finally 

 becoming coated with its horny and siliceous spicular cortical 

 coat. 



This being the case, I propose to abandon the sections 

 Malacosporoi and Cldamydosporcv ^ and to retain the orders 

 Bphoirospongia and Potamospongia^ only rendering their cha- 

 racters more consistent with our present knowledge of the 

 subject. This systematic distribution is considered only a fiist 

 attempt at arranging the genera of sponges in a systematic 

 order, according to an analytical method. It is doubtless very 

 incomplete, but it has the advantage of being capable of any 

 extension that may be required ; and I shall consider it a step 

 in advance if it allows naturalists to be able to say at once to 

 what group a majority of the sponges they examine will be- 

 long. I am aware that there do occur sponges which are 



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