322 E. RAY LANKESTER. 



mitted by rae to the readers of that journal^ publicly to with- 

 draw the charges of theft made by him, though he has not had 

 the manliness to apologise for his attempt to injure a scientific 

 confrere. On the contrary, he continues to exhibit an un- 

 worthy spite, which I need not notice in detail. 



Mr. Hermann Jhering has published two papers on the 

 development of Mollusca,^ in which he has criticised my 

 observations upon the development of Pisidium. He is 

 good enough at the outset of his remarks relative to myself to 

 allude to the ' staunenswerthe Unkenntniss ' and ' zugel- 

 lose Phantasie des Autors.' This rough sort of abuse though 

 unmannerly is not such as to call for a reply. We are not 

 accustomed to it in this country in scientific literature, but 

 those of us who read German periodicals know that it 

 is more frequently met with in those publications, and 

 is merely the fashionable way of saying that you disagree 

 with a brother zoologist. Mr. Jhering, however, goes on 

 further with his criticism, and entirely misrepresents my 

 views. He says (' Jenaische Zeitsch.,' vol. ix, p. 311), 

 " E-ay-Lankester regards the byssus-gland of the Acephala 

 in so far as its secretion is concerned, as not only the first 

 rudiment of the shell - ligament of the mussel shells, but 

 he declares that it exists also in Limnseus under the shell 

 in relation with the mantle — ground enough for him to 

 pronounce straightway the internal shell of Limax to be 

 homologous with it (the byssus-gland), his shell-gland." 

 He proceeds further to declare that I have apparently never 

 heard of the byssus-gland. Not for the benefit of Mr. Jhering, 

 who appears to write with the humorous intention of 

 making as much confusion as possible, but for the sake of 

 those who might accept what he has said in the ' Jenaische 

 Zeitschrift ' and in the * Zeitschr. fiir Zoologie ' seriously, 

 I will point out that there is not the remotest ground for 

 supposing that I have mistaken the byssus-gland for the 

 shell-gland in Pisidium. When I discovered the shell-gland 

 in Pisidium it was unknoion in that or any other mollusc. I 

 was perfectly well acquainted with Leydig's and Schmidt's 

 observations on the development of Cyclas, and I looked for 

 the byssus-gland in its proper place. So far as I followed 

 Pisidium (up to the development of four gill-filaments only), 

 no byssus-gland is developed. In Cyclas it does make its 

 appearance before that stage, as do also the oto-cysts, which 

 certainly do not appear so early in Pisidium. I did not 



' 1, "Ueber die Entwickelungsgeschichte von Helix," ' Jenaische Zeit- 

 schrift/ vol. ix, p. 299 ; and 2, ' Ueber die Ontogenie von Cyclas " (devoid 

 of illustrations), ' Zeitschrift fiir Wiss. Zoologie,' Bd. xxvi, p. 414. 



