A GENERAL OUTLINE 



OF 



THE ANIMAL KINGDOM. 



CHAPTER I. 



ON CLASSIFICATION. 



(1.) FROM the earliest periods to the present time, the great desi- 

 deratum in Zoology has been the establishment of some fundamental 

 system of arrangement which, being universal in its application, should 

 distribute the countless beings surrounding us into natural groups or 

 divisions, such as might be subdivided into classes, orders, and genera, 

 by obvious differences of structure in the tribes composing them, and 

 thus enable the Zoologist at once to indicate the position which any 

 unknown animal ought to occupy in the scale of existence, and its 

 relations with other creatures. 



(2.) Aristotle, the father of our science, was the first who attempted 

 a scientific division of the animal world *. The outlines of his system 

 were rude in proportion to the necessarily limited knowledge at his 

 disposal, although his efforts were gigantic, and still excite our warmest 

 admiration. This acute observer admitted but two great sections, in 

 one or other of which all known beings were included, the highest 

 comprehending creatures possessed of blood (i. e. red blood), corre- 

 sponding to the YERTEBRATA of modern authors ; the lowest embracing 

 animals which in his view were exsangueous, or provided with a colour- 

 less fluid instead of blood, and corresponding to the INVERTEBRATA of 

 more recent zoologists f. 



(3.) Linnaeus, like Aristotle, selected the circulatory system as the 



* Historia Animalium. 



t IIpos $e TOVTOIS TO. f^ev evctifjia rvy^avei ovra, olov dv9p<t)Tro$ Kai ITTTTOS Kai 

 ndvQ' otra 77 ctTroSa e<m reXea OVTCL r\ Terpairoda, TO. d' dvaifia, olov fieXiTra ical 

 <T0>} Kai TUV OaXarriiov (T7/7rta Kai KcipajSos Kai TrdvO' oaa TrXeiovs Trodas e%ei 

 rerrapwv. Hepi Zwa 'laroptov, Ke0. A. 



B 



