120 DR. J. S. BOWERBANK ON SPONGES. [Feb. 13, 



are certainly recognized by the aid of the microscope with greater 

 decision and faciUty than those of many other branches of zoology 

 or of botany. 



Having thus assigned the skeleton to the determination of genera, 

 it became a question as to what parts of the organization were the 

 most appropriate to the distinction of the species. H?re, again, the 

 lucid example of the great father of systeniatical botany, Linnaeus, 

 naturally suggested the most advisable course of proceeding ; and the 

 example that he set botanists in a rigid examination and a compen- 

 dious nomenclature of those parts of the plant that were rather 

 auxiliary and only occasional in their presence, and not absolutely 

 necessary to the existence of a plant, naturally suggested the course 

 to be pursued with regard to the determination of the species among 

 the Spongiadae ; and first amidst these characters stood forth the 

 spicula, the fit compeers of the leaves of plants in their great variety 

 of form ; and, like them, they are as widely distributed and as com- 

 pletely without reference to generic peculiarities. Other subsidiary 

 organs in the sponges have also their value as specific characters, and 

 have been thus applied accordingly ; but among these form and 

 colour, the sheet anchors of the old modes of arrangement, are un- 

 doubtedly of the least value, from the perfectly protean character of 

 the first, and the variable and evanescent peculiarities of the latter. 

 My first task, therefore, was to acquaint myself, as completely as I 

 possibly could, with the various normal forms, and their varieties, of 

 the spicula and their especial situations and peculiar offices in the 

 animal economy. In aid of this object, I accumulated a vast number 

 of specimens from various quarters of the world ; and as each pecu- 

 liar form of spiculum became known to me I had to record and dis- 

 tinguish it by a name, as I found no such thing as a systematic de- 

 scription or nomenclature of the organisms of the Spongiadae existing. 

 How far I may have executed this task to the satisfaction of the 

 scientific world I must leave time to decide, and, where necessary, to 

 correct. In thus attempting to establish a nomenclature of parts 

 hitherto undescribed, I have endeavoured to make these terms ex- 

 pressive of the forms and qualities of the organs in the same manner 

 as the designations of leaves more or less describe their forms and the 

 modes of their arrangement. But this one thing is certain, that 

 without a definite nomenclature no descriptive science can hope to 

 progress with any degree of precision or success. 



My first application of the nomenclature thus formed was origi- 

 nally published in the ' Philosophical Transactions,' as I have before 

 stated ; and it has been applied to the British species of sponges in my 

 monograph of them published by the Ray Society. 



This work, Dr. Gray is of opinion, is hot sufficiently distinct and 

 definite in its descriptions to answer the required purpose ; and he 

 seeks to remedy this defect by his proposed new mode of arrangement, 

 which is based principally on the forms and peculiarities of the spi- 

 cula, totally ignoring the skeleton as a means of arrangement into 

 orders or genera. 



It would require almost a volume to discuss and expose the fallacy 



