Scientific Reviews. 39 



coveries, to wliich I have been the first to do justice in the report 

 which I gave of them to the Academy. There are, further, fea- 

 tures which he has added to the different degrees of resemblance 

 which exist between the composition of different animals ; but he 

 has only added to the ancient and well known bases of zoology, he 

 has not changed them in the least. 



" Thus all naturalists knew, for a long time, that the cetacea 

 have on the side of the anus two little bones called the rudiments 

 of the pelvis. There is then, in this case, and it has been known 

 for centuries, a slight resemblance of composition ; but nothing can 

 make us believe that there is unity of composition, when this ves* 

 of a pelvis gives support to none of the bones of the lower extre- 

 mity. 



" In one word, if by unity of composition they mean identity, 

 they say a thing contrary to the testimony of the senses. 



" If by it they mean resemblance, analogy, they say a thing that 

 is true in certain limits, but as old in its principle as zoology itself, 

 and to which the most recent discoveries have only added, in cer- 

 tain cases, more or less important features, without altering any 

 thing in its nature." 



Further, in this important and ancient principle, Mr. Cuvier, 

 and it is more particularly herein that he differs from the natural- 

 ists whose opinion he combats, is far from considering it as a single 

 principle ; on the contrary, he only sees a principle subordinate to 

 one more elevated and much more fruitful — the conditions of ex- 

 istence, the conformity of parts, and their co-ordination for thi 

 ■place which the animal is to fill in nature. Stich, he considers, is 

 the true philosophical principle from which the possibility of cer- 

 tain resemblances may flow, and the impossibility of others. Such 

 is the rational principle whence that of analogy, of plan, and of com- 

 position, is deduced, and in which, at the same time, it meets with 

 limits which we vainly attempt to overlook. 



The reality of a certain analogy of composition and of plan be- 

 ing known, naturalists have nothing else to do, and they in fact do 

 nothing else, than examine how far the resemblance may extend,— 

 in what cases, and on what points it rests, and if there are beings 

 where it is so far reduced as to be said to be absent. It is the spe- 

 cial object of comparative anatomy, which is far from being a mo- 

 dern science, since its first author was Aristotle. 



Mr. Cuvier entered into the details of the discussion in the point 

 of view announced by JMessrs. Laurencet and Meyraut, wherein 

 the mollusca are considered as species of vertebrated animals, bent 

 backwards at the umbilicus, so that the two portions of the spine 

 of the back come in contact. To appreciate the justice of this view, 

 Mr. Cuvier took, on the one hand, a vertebrate animal, in which he 

 bent, as was required, the pelvis towards the back part of the neck, 

 and lifted away the integuments of one side, to expose the internal 

 parts in that situation. On the other hand, he took a cuttle-fish. 



