RETROGRESSION. l8l 



analogies between the circular system of the birds and 

 that of the Mammals : 



Primary Types. Orders of Birds. Typical Characters. of Mammals. 



1. Typical Insessores Organs of prehension Quadrumana 



(Perchers). and general struc- (Monkeys), 

 ture highly de- 

 veloped. 



2. Sub- typical... Raptores Carnivorous, claws re- Feres (Beasts of 



(Birds of tractile. Prey). 



Prey). 



3. Aberrant Natatores Live and feed in the Cetacea (Whales, 



(aquatic (Swimmers), water. Feet short, Dolphins, &c.) 

 group). or none. 



4. Aberrant Grallatores Jaws much prolonged ; Glires (Rodents 



(suctorial (Waders). burrow for their and most 

 group). food. Marsupials). 



5. Aberrant Rasores Head with crests of Ungulata 



(rasorial (Scratchers). horn or feathers; (Hoofed 

 group). habits domestic ; Quadrupeds). 



feet long, formed 



for walking. 



Swainson excuses himself for not entering into long 

 details explanatory of the above table, on the ground 

 that explanation is unnecessary, seeing that ' the analogies 

 are so perfect, and the series so completely in unison 

 with those of all other animals. 7 To the modern scientific 

 student it seems equally unnecessary to discuss such a 

 table, as it violates all those fundamental canons of 

 classification which have been established by the com- 

 bined labours of naturalists for the last two centuries. 

 It would not, indeed, be easy to produce a classificatory 

 table of Mammals and birds more entirely at variance 

 with what naturalists at the present day believe as to 



