on Sponges from the Antarctic Sea and from Shetland. 59 



p. 148, vol. i. of ' Monograph of the British Spongiadse/ that I 

 liave stated that that species has the same description of gem- 

 mule as the larger of the two described as belonging to T. 

 cranium^ but that the smaller and more simple ones which 

 accompany the large one in that species are not present in 

 the college specimen of T. simillima. A difference in the 

 amount of the projection of the spicula beyond the margins of 

 some parts of the object prepared for microscopical observa- 

 tion, as represented by Mr. Carter in his pi. xx. fig. 2, is 

 very likely to be caused by the process of preparation for ex- 

 amination. In the natural condition, as represented in the 

 gemmules of T. cranium^ in ' Mon. Brit. Spongiadae,' pi. xxv. 

 fig. 344, they do not appear beyond the external membrane of 

 the gemmule. These facts are all stated in p. 147 of vol. ii. 

 of my work, and might have been readily verified by Mr. 

 Carter from the specimens of T. cranium in the British 

 Museum, had he taken the trouble to carefully examine 

 them. The fact of their not appearing beyond the surface of 

 the genimule militates strongly against Mr. Carter's imaginary 

 base with its anchoring spicula ; and neither in the adult state 

 of the specimens of T. simillima^ nor in any other among the 

 ten species with which I am familiar, are there any such an- 

 choring spicula in their natural state. 



The author, in the last paragraph of p. 410 of his paper, 

 has evidently fallen into the error of imagining that the 

 '^ ovum or, rather, young Tethya " is, in point of structure, the 

 exact representative of the mature sponge, when, in truth, a 

 very considerable difference in structural arrangement exists 

 between them — that is, if we are to take Tethea cranium^ 

 the structure of which we do know, as our example of the 

 anatomy of the fully developed sponge and the gemmules 

 within it. 



Mr. Carter appears to have been somewhat shocked by 

 finding a jar at the British Museum labelled " ' Shetland. J. 

 S. Bowerbank, 52. 3. 12. 70-73,' to which is added, in Dr. 

 Bowerbank's blue ink and handwriting, ' Tethya lyncurium.^ " 

 I think Mr. Carter will find that I have not labelled the jar 

 Tethya but Tethea, if I have labelled it myself at all. At 

 this distance of time I only recollect that I gave some British 

 Sponges to the British Museum, and that among them were 

 several specimens of Tethea cranmm ; and whether I mis- 

 labelled the jar myself inadvertently, or the label was cut 

 from the list of species sent, and so stuck on it in error, I really 

 cannot say ; the numbers on the label were certainly not put 

 on by me. In this jar Mr. Carter found " six specimens, two 

 of Tethya cranium and four of another species of Tethya as 



