466 The Lepidosiren : a Fish ? or a Reptile ? 



The slight attention, however, that has hitherto been be- 

 stowed upon these animals, and the difficulty of capturing 

 them, renders it not improbable that other species may exist. 

 Still it seems very doubtful whether the true Phoca barbata 

 has ever yet been found upon the British shores. 



LIV. — On the natural affinities of the Lepidosiren; and on 

 the differing opinions of Mr. Owen and M. Bischoff with 

 regard to them. By M. Milne Edwards*. 



When Zoology is only studied in systematic works, it is often 

 supposed that each class, each family and each genus, pre- 

 sent to us boundaries precisely defined, and that there can be 

 no uncertainty as to the place to be assigned in a natural 

 classification to every animal, the organization of which is 

 sufficiently known ; but when we study this science from na- 

 ture herself, we are soon convinced of the contrary, and we 

 sometimes see the transition from one plan of structure to an 

 entirely different scheme of organization take place by de- 

 grees so completely shaded one into the other, that it be- 

 comes very difficult to trace the line of demarcation between 

 the groups thus connected. The inferior animals present 

 many examples of such gradations ; and now comes the Le- 

 pidosiren to unite, in the same manner, two classes of verte- 

 brate animals, which, till now, had been supposed to be sepa- 

 rated by perfectly clear limits. We have, in fact, seen that 

 in certain respects this singular animal resembles Fish, whilst, 

 by other characters equally drawn from its organization, it 

 does not differ from Reptiles. 



This mixture of the ichthyological type and of the herpe- 

 tological type is indeed so complete, that the two naturalists 

 who have best studied the structure of the Lepidosiren dis- 

 agree as to the intimate nature of this animal. In one of our 

 preceding numbers our readers have seen the analysis of Mr. 

 Owen's labours, and the reasons which induced this skilful 

 anatomist to believe that the Lepidosiren was to be regarded 

 as a Fishf; whilst from another equally accurate investiga- 

 tion by M. Bischoff, a translation of which J has been given 

 :n the Annales des Sciences Naturelles, the author draws the 



* From Annales des Sciences Naturelles for Sept. 1840. Zool. p. 159. 



if* See Annales des Sciences Naturelles, 2me Serie, tome x. p. 371. 



Mr. Owen's Memoir on the Organization of the Lepidosiren annectens 

 makes a part of the 18th volume of the Transactions of the Linnsean Society 

 of London. For an abstract of this paper, read April 2, 1839, see Annals 

 of Natural History, vol. iii. p. 265. 



I From a Memoir published at Leipzig in 1840, in 4to. 



