60 Dr. J. S. Bowerbank on Mr. Carter's Paper on Sponges. 



yet Tindescribed ; " and the latter specimens he subsequently- 

 described as Tethya antarctica. Mr. Carter seems to have been 

 exceedingly fortunate, if he be correct in his conclusions, in find- 

 ing four specimens of a new species, as immediately on reading 

 his observations on them I set myself to carefully examine 

 the remainder of my stock of T. cranium^ more than a hundred 

 specimens, varying in size from a pea to an average-sized 

 orange ; and I could not find a single specimen among them 

 that could not be satisfactorily identified as T. cranium. I 

 therefore feel strongly inclined to believe that Mr. Carter has 

 fallen into the error of making from small, unimportant dif- 

 ferences in the same sorts of structures, two species out of 

 one ; but the dots and lines he has given in illustration of his 

 paper are so vague and unsatisfactory, that they do not at all 

 assist us in unravelling the mystery. The description of the 

 gemmules of his T. zetlandica would apply quite as well to 

 those of T. cranium ; and every form of spiculum that he 

 figures as from the former, may be readily found in the latter 

 species. 



The author, in p. 419, treating of " the small globular and 

 compressed elliptical bodies " or gemmules of Tethea, writes, in 

 the second paragraph, " In Dr. Bowerbank's ' British Sponges,' 

 pi. 25. fig. 343, will be found a monstrous representation of one 

 of these oviform bodies under the designation of ' gemmule,' 

 which is only surpassed by his description (vol. ii. p. 87), 

 where he applies the term ' sexual ' to them, and conjectures 

 that one may be the ' female or prolific gemmule ;' but Dr. 

 Bowerbank had never been able to discover any ' spermatozoa ' 

 in either ! As this is a kind of physiology that I do not un- 

 derstand, let us go back to the term oviform &c." 



If the author of the paper, in place of criticising the represen- 

 tation of the gemmules of T. cranmm in vol. i. pi. 25. fig. 343, 

 and the description of them in vol. ii. p. 87, of the ' Monograph 

 of British Sponges,' in the flippant manner in which he has 

 indulged, had communicated with me on the subject, I could 

 have informed him that, instead of illustrating the anatomy of 

 the subjects under consideration by dots and lines, the figures 

 alluded to were drawn from the preparation still in my pos- 

 session, by the aid of the microscope and the camera lucida, 

 by one of the most talented and accurate microscopical artists 

 that we have among us, Mr. W. Lens Aldous, and that his 

 representation of the originals is not in the slightest degree 

 exaggerated ; on the contrary, the figure of the larger of the 

 two is that of a gemmule rather less complicated in its struc- 

 ture than many of those closely adjoining it, in a slice of the 

 sponge immersed in Canada balsam, about four lines square, 



