Miscellaneous. 389 



his back in his eagerness to accomplish the task. It was impossible to 

 witness the actions of this animal without being struck by the amount 

 of skill and intelligence exhibited. When the space cut through 

 towards the centre was too narrow to admit its head, its teeth were 

 applied above and below so as to increase the width from the outside 

 towards the centre, until the remaining parts above and below formed 

 two cones, the apices of which joined in the middle. Again and again 

 the animal left off gnawing, and, standing upright on its hind legs, 

 rested its front feet on the upper part of the tree, as if to feel whether 

 it was on the move. This showed clearly that the creature knew 

 exactly what it was about. 



MISCELLANEOUS. 



' The Land and Freshwater Mollusks of the British Isles' 

 To the Editors of the Annals and Magazine of Natural History. 



Gentlemen, — While thanking you for your notice of my little 

 book, ' The Land and Freshwater Mollusks of the British Isles,' I 

 beg permission to offer a word of comment on some remarks therein 

 made on some changes in nomenclature. Your reviewer says : — 



11 Planorbis imbricatua is changed to Planorbis crista, on the 

 authority of the following synonymy : — 



"Nautilus crista, Linnaeus (1758), Syst. Nat. 10th edit. p. 709. 



" Turbo nautileus, Linnaeus (1767), Syst. Nat. 12th edit. p. 1241. 

 " And the author remarks, — ' It may be observed, on reference to the 

 synonymy, that Linnaeus made two species of this.' But Linnaeus 

 did not make two species out of Planorbis nautileus. The facts are 

 that he described Nautilus crista in the tenth edition of the 'Systema 

 Naturae ; ' and in the twelfth edition changed the name of the species 

 to Turbo nautileus, and referred to his Nautilus crista of the tenth 

 edition as a synonym. We can only account for Mr. Reeve's mistake 

 by supposing that he has never consulted the twelfth edition — a sup- 

 position which is confirmed by the fact that throughout his volume 

 the tenth edition is almost invariably referred to." 



As this declaration of opinion involves a principle in nomenclature 

 to which I cannot agree, I beg leave to state that I purposely referred 

 throughout my volume to the tenth edition of the ' Systema Naturae' 

 for the authority of the Linneean species, after the example of M. 

 Moquin-Tandon, because it is the first edition in which the species 

 are established by the definition of specific names and characters. I 

 followed also Moquin-Tandon in adopting the name of crista given 

 to this Planorbis in the tenth edition of the ' Systema Naturae,' be- 

 cause I agree with the learned author of the ' Mollusques Terrestres 

 et Fluviatiles de France ' in thinking that Linnaeus was not justified 

 in changing it, in his twelfth edition, to nautileus. An author is no 

 more justified in changing his own established name of a species than 

 any other writer would be. 



With reference to your reviewer's observations on my remark that 



