4 MANUAL OF NATURAL HISTORY. 



throughout her works erects no lofty barriers, no 

 visible boundaries ; for however well marked the cen- 

 tral portions of her various territories may seem, yet 

 on their confines they are so closely united, so inti- 

 mately combined, as to blend her entire domains into 

 a perfect and harmonious whole. 



The most simple division of the Animal Kingdom 

 is into Vertebrates and Invertebrates, the latter 

 being again divided into four sub-kingdoms. These 

 are distributed into classes, orders, sub-orders, and 

 families, which is the extent to which we shall trace 

 them in the following pages ; as an enquiry into sub- 

 families, genera, sub-genera, and species, would be 

 perfectly impracticable within the limits of a portable 

 volume. The system of nomenclature adopted is as 

 uniform as circumstances allow, especially in the case 

 of the families, which, according to the prevalent 

 zoological views of the day, are always indicated by 

 ending in idee. 



CLASSIFICATION OF THE ANIMAL 

 KINGDOM. 



I._$UB-KINGDOM. YEHTEBEATE ANIMALS. 



Vertebrata, Guv. Spinicerebrata, Encephalata, 

 Grant Myelencephala, Owen. 



1 Class Mammals (Mammalia, Mammifera) 



2 „ Birds (Aves) 



3 „ Reptiles (Reptilia) 



4 „ Amphibians (Amphibia) 



5 „ Fishes ; (Pisces) 



