STATEMENT OF THE SUBJECT. 5 



into the under surface of the body. In Radiates, the 

 germ occupies the whole periphery of the sphere. 



Of the four branches of the Animal Kingdom, the 

 Vertebrates are unquestionably the highest in rank, and 

 the Radiates lowest ; while of the other two it is not 

 easy to say which, on the whole, is the higher, and which 

 the lower branch. And here a word of explanation is 

 due in regard to the rank of animals. 



In one sense, all animals are alike perfect. Each is 

 perfectly adapted to fulfil its own peculiar office in the 

 great economy of nature. In this sense, every animal is 

 perfect. But in regard to organization there is every 

 grade, from those of the most extreme simplicity, and 

 with the most simple functions, to those of the highest 

 possible complication, and with the most numerous, va- 

 ried, and complicated functions. Now an animal is 

 higher according to its higher complication of structure, 

 and hence more numerous and varied functions. 



In the subsequent pages we examine somewhat care- 

 fully these four branches of the Animal Kingdom, taking 

 them in the order named above. One chapter is de- 

 voted to each Branch, one section to each Class, one 

 sub-section to each Order. Paragraphs marked with 

 small capitals introduce each Family. The Genera are 

 given in italics, the popular name of Species in ordi- 

 nary type, and the scientific name immediately follows 

 in italics. 



