Prof. J. V. Barboza du Bocage on Hyalonema lusitanicura, 125 



This is pretty nearly what I have replied to Professor Ehren- 

 bcrg; but I am sure that he will maintain his first notion. It 

 is his fixed idea. 



There is, however, in what Professor Ehrenberg has written 

 to me a question of fact, which I beg you to verify and get veri- 

 fied. M. Ehrenberg asserts that he has been able to place be- 

 yond doubt the presence of cotton threads attaching the different 

 pieces of the Hyalonema. Now I beg you to examine with the 

 utmost care the specimens which you possess, and in which M. 

 Ehrenberg asserts that he has found this proof oi artificial fabri- 

 catiun, and be kind enough to communicate to me the result of 

 your examination. 



For my part I have examined with scrupulous attention the 

 six specimens which I possess ; and not one of them presents 

 the least trace of cotton threads, or anything which would lead 

 one to believe in their artificial fabrication. The power of a 

 preconceived idea is such that it will make us see cotton threads 

 and signs of human fabrication in perfectly natural products in 

 which they do not exist ! 



The confidence with which M. Ehrenberg writes to me about 

 this throws me into the deepest astonishment. On my side 

 there is not the least question of self-love. I am disposed 

 to change my opinion in the presence of good arguments ; 

 but I cannot accept as such perfectly absurd hypotheses. I 

 have also just read, in the 'Annals and Magazine of Natural 

 History" (March 1867), the article by M. Max Schultze. He 

 still believes in his sponge ; but, although agreeing on this point 

 with Dr. Bowerbank, he does not admit that the polypes also 

 belong to the sponge. Quot capita, tot sententice. 



Excuse me for having written you such a long letter, and 

 accept, &c. 



J. V. Barboza du Bocage. 



My dear and honoured Confrere, Lisbon, June 16, 1867. 



Professor Ehrenberg^s incredulity with regard to the habitat 

 of Hyalonema lusitanicuni has driven me to undertake a journey 

 to Setubal, in order to obtain all desirable particulars on the 

 spot. The following is a summary of the rigorous inquiry 

 which I have just carried out. 



The Hyalonemas are well known not only to the shark-fishers 

 and the proprietors of fishing-boats, but also to several people of 

 good position in the town. They call them " chicotes de marj" 

 that is to say, " sea-whips.^^ It is since 1863 that the shark- 

 fishers have most frequently found Hyalonemas attached to their 

 fishing-apparatus ; nevertheless some persons remember having 



