272 ON THE CLASSES OF THE 



Having been warned by the author that we are not to con- 

 sider this series as a scale of perfection in structure, nothing 

 ought to be said on the subject. It is the order of affinity 

 which is held forth as the merit of this short list ; and yet here 

 we have the Seal placed next to the Kangaroo, the Hare 

 next to the Sloth, the Ornithorhynchus allied to the Ele- 

 phant, the Ox to the Whale, and this animal again to the 

 Birds of Prey. In short, the discrepancies are so great and 

 so frequent, that we necessarily pause before we can 

 admit that such can be a series of animals distributed 

 according to their organization. Be this however in ge- 

 neral as it may, there is one thing very certain, that the 

 Cetacea lead us by a very distinct and natural transition 

 from the Mammalia to Fishes • and that if their warm 

 blood, their lungs, their viviparous generation and mamma; 

 prove their affinity to the former group, their skeleton and 

 external covering, the imperfection of their olfactory and 

 auditory organs, all show that they approach near to fishes. 

 The viviparous sharks, such as Selache maxima Cuv. or 

 Basking Shark, with their ear more perfectly organized 

 than that of other fishes, and their body detitute of scales, 

 the particular disposition of their fins, and their closed 

 branchiae, all indicate at what place we are to enter among 

 the fishes. With the exception of such sharks, fishes are 

 oviparous animals, whose eggs are fecundated by the male 

 shedding his milt over them. They breathe by branchiae; 

 and the blood, after respiration, passes into an arterial 

 trunk situated under the spine, and which performing the 

 functions of the left ventricle disperses it throughout the 

 body, from which it again returns by means of the veins. 

 Nothing is as yet known of their natural arrangement; 

 but it is allowed by every naturalist that they are inti- 

 mately connected with the Amphibia or Batraciens of 



