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



Sicily by Mr. Topping and was presented to me by him. Now the 

 question arises, which of these new genera and species are to stand ? 

 are either or neither? Common sense would answer, the latter. 

 One would naturally imagine that this facility in creating genera 

 could not be carried to a more absurd extreme ; but, strange as it 

 may appear, under the ingenious manipulation of Dr. Gray, that is 

 really the case, as in page .544, the genera and species, 14. Acarnus 

 innominatus, and 15. Fonteia anomala are actually founded on one 

 form of spiculum hitherto only found on one undescribed species of 

 sponge. Acarnus innominatus is, derived from fig. 292, pi. 18, 'Mon. 

 Brit. Sponges,' representing a portion of the reticulated skeleton of 

 the sponge with the radiating fasciculi of spinulo-quaternate internal 

 defensive spicula w situ; while Fonteia anomala is based on the figures 

 73-76, pi. 3, of the same work, representing the various stages of 

 development of the same spinulo-quaternate spicula as those repre- 

 sented in situ in pi. 1 8, and which various forms are described by me in 

 page 239, 'Mon. Brit. Spongiadae,' as diiferent stages of development 

 of the perfect form represented by fig. 7^, and the reader is referred 

 to pi. 18. fig. 92, in the same description, for a view of them «« situ. 

 Comment on such a case as this is superfluous ; and, strange though 

 it be, the author, with their descriptions before his eyes, describes them 

 as "spicules of four kinds." If the author should steadily pursue the 

 course described in the last cases we may ultimately arrive at the un- 

 foreseen and rather extraordinary conclusion that not only may single 

 species represent a genus, but an individual may really be composed 

 of a group of genera and species. 



I will now endeavour to show the mischievous consequences, to 

 closely allied and well-established genera, arising from Dr. Gray's 

 mode of founding his new genera on peculiarities of form in the 

 various auxiliary spicula of sponges, which are only present in certain 

 species, and which vary more or less in form, combinations, and 

 mode of disposition in almost every species in which they are found, 

 instead of basing his generic characters on the more substantial and 

 enduring characters afforded by the anatomical peculiarities of the 

 skeleton. I will not comment on every instance in which his mode 

 of proceeding has been highly detrimental to our power of discrimi- 

 nating species, but I will select a few only of the most illustrative 

 ones. Thus in the genera Tethea and Geodia we have two of the 

 most natural and most accordant groups of species among the whole 

 of the Spongiadse, groups which all naturalists have hitherto con- 

 curred in preserving entire. Let us see how the author proposes 

 to treat them. 



In the first place, Dr. Gray, in page 543 of his paper, misquotes 

 hoth Dr. Johnston's ' History of British Sponges,' page 85 (or, more 

 correctly, 83), and my 'Monograph of British Spongiadae,'vol. ii. page 

 83, making us each to have adopted the term Tethya, whereas both 

 have rejected that name and adopted Lamarck's name Tethea, for the 

 very good reasons given by Dr. Johnston in page 83 of his work. 

 Dr. Gray separates Johnston's two species T. cranium and T. lyn- 

 curium, leaving the former as the type of his Tethya, page 543, 



