APPENDIX. 351 



tlieir preparations. Phlebenterism was declared to be 

 entirely exploded, and characterised as a mere chimera. 



It so happened, however, that my opponents, who 

 were agreed in declaring me convicted of flagrant errors 

 (/ have considerably softened these expressions), were far 

 from agreeing amongst themselves. It is curious to 

 compare in this respect the remarks of M. Souleyet in 

 France, and Professor Allman in England, in respect to 

 the Acteons*, one of the most curious genera of this 

 group. That which is regarded by the one as a circula- 

 tory apparatus is in the eyes of the other a complete 

 respiratory apparatus. That which the one calls a 

 sanguiniferous vessel, the other calls an aquiferous 

 trachea; the auricle of the one is in the eyes of 

 the other a sac, communicating externally by means 

 of an orifice. Finally, while the one declares that 

 Acteons are Molluscs, allied to the EolidaB, as I had pre- 

 viously stated was the case, the other, who is the re- 

 presentative of old ideas, would have these animals 

 remain near the Aplysiae. These fundamental discre- 

 pancies do not, however, prevent these naturalists from 

 congratulating each other on the perfect accordance 

 of their views. (See the memoirs of Allman in the 

 Annals of Natural History, and of Souleyet in the 

 Comptes rendus.) 



This mistake on the part of two conscientious natural- 

 ists in reference to their reciprocal mode of seeing the 

 same thing was the more remarkable, because they were 



* Contrary to what has been stated, the genus Acteon comprises 

 several species differing essentially from one another. In the place 

 of dorsal papillae, we find in all of them a broad, but thin expansion, 

 which is prolonged posteriorly in the shape of a leaf, and surrounds 

 the body. The intestinal ramifications are distributed throughout 

 the whole of this lamina, which, moreover, encloses the reproductive 

 organs. 



