APPENDIX. 521 



The larynx, size of trachea, and number of ribs, 

 differ exceedingly. The coecum is only found in 

 some of them. The teeth in some are wanting. 

 The blow-holes are two in number in many ; in 

 others only one. The Whalebone and Spermaceti 

 are peculiar to particular genera ; ail which con- 

 stitute great variations. In other respects we 

 find an uniformity, which would appear to be in- 

 dependent of their living and moving only in the 

 water, as in the stomach, liver, kidneys, &c. 



From the tail bemg horizontal, the motion of 

 the animal, when impelled by it, is up and down : 

 tM^o advantages are gained by this ; it gives the ne- 

 cessary opportunities of breathing, and elevates 

 them in the water ; for every motion of the tail 

 tends to raise the animal ; and that this may be 

 effected, the greatest motion of the tail is down- 

 wards, those muscles being very large, making 

 two ridges in the abdomen : this motion of the 

 tail raises the anterior extremity, which always 

 tends to keep the body suspended in the water. 



The bones alone, in many animals, when pro- 

 perly united into what is called the skeleton, give 

 the general shape and character of the animal. 

 Thus a quadruped is distinguished from a bird, 

 and even one quadruped from another, it only re- 

 quiring a skin to be thrown over the skeleton to 

 make the species known ; but this is not so de- 

 cidedly the case in this order of animals, for the 

 skeleton in them does not give us the true shape. 

 An immense head, a small neck, few ribs, and in 

 many a short sternum and no pelvis, with a long 



