1868.] DR. J. S. BOWERBANK ON SPONGES. 127 



leton in this family as " consisting of simple filiform spicules, 

 with three prongs or three recurved points at the outer end." This 

 is inaccurate. The skeleton of Tethea cranium, Johnston, which 

 the author has selected as the type of his family, is composed of 

 simple fusiformi-acerate spicula, the fusiformi-porrecto-ternate and 

 fusiformi-recurvo-ternate ones being purely external defensive spi- 

 cula (Mon. Brit. Spon. vol. ii. p. 83). 



The Genera. 



Having discussed the general principles of Dr. Gray's new sys- 

 tematical arrangement of the sponges in his classes, orders, and 

 families, we will now proceed to consider the mode in which he 

 proposes to establish his numerous new genera ; and it will perhaps 

 facilitate our comprehension of his scheme if we first consider tiie 

 present condition and numbers of the genera in contrast with the 

 characters and numbers of Dr. Gray's new series of them. 



The author proceeds in the first place to adopt to a considerable 

 extent the genera established by previous writers on the Spongiadse, 

 altering the phraseology according to his own ideas of terminology, 

 sometimes omitting, as in his character of Stematumenia (p. 511), 

 the most distinctive character of the genus, the fibro-membranous 

 tissues, and then adding a variety of characters derived from the 

 specific ones of the type species of the genus he adopts, thus 

 completing the heterogeneous mixture of descriptions. In this mode 

 the author has adopted sixteen genera from Professor O. Schmidt's 

 ' Die Spongiea des Adriatischen Meeres,' twenty-nine from my 

 ' Monograph of the British Sponges,' and seven others from various 

 authors, making a total of fifty-two genera. The number of genera 

 treated of in Dr. Gray's paper is 157, so that we have a total of 

 105 new genera proposed to be established ; and these, we shall find, 

 are based upon the descriptions of species hitherto comprised in the 

 genera of the authors quoted above, with alterations to suit the occa- 

 sion. And, finally, others are founded on the descriptions of single spi- 

 cula, described in the anatomical portion of vol. i. of my 'Monograph 

 of British Spongiadae' as examples of organic form, without the 

 slightest knowledge on his own part of the sponges whence they 

 were derived. 



In the construction of his families, we have seen that the course 

 pursued by Dr. Gray has been that of appropriating every known 

 genus within his reach, without the slightest consideration of the 

 different and perhaps discrepant principles on which they have been 

 based by their respective authors. The same mode is adopted by 

 him in his proposed new genera. 



Every species having a determinate specific character is at once 

 seized upon by Dr. Gray, and converted into a new genus ; and it 

 seems to matter little to him whether the specimen the characters 

 of which are thus appropriated be in his own possession or the pro- 

 perty of a private collector, as, in the latter case, it is surreptitiously 

 taken, withoiit the least regard to the owner of the specimen, or 



