FAMILIES. 245 



obtain a glimpse of what may fairly be called families, 

 few investigations require more patient comparisons than 

 those by which we ascertain the natural range of modi- 

 fications of any typical form, and the structural features 

 upon which it is based. Comparative anatomy has so 

 completely discarded every thing that relates to Morpho- 

 logy, and the investigations of anatomists lean so uni- 

 formly towards a general appreciation of the connections 

 and homologies of the organic systems which go to build 

 up the body of animals, that, for the purpose of under- 

 standing the value of forms and their true foundation, they 

 hardly ever afford us any information, unless it be here 

 and there a consideration respecting teleological relations. 



Taking for granted that orders are natural groups 

 characterized by the complication of their structure, and 

 that the different orders of a class express the different 

 degrees of that complication, taking now further for 

 granted that families are natural groups, characterized by 

 their form as determined by structural peculiarities, it 

 follows that orders are the superior kind of division, as 

 we have seen that the several natural divisions which are 

 generally considered as orders contain each several natu- 

 ral groups, characterized by different forms, that is to say, 

 constituting as many distinct families. 



After this discussion it is hardly necessary to add, that 

 families cannot by any means be considered as modifica- 

 tions of the orders to which they belong, if orders are to 

 be characterized by the degrees of complication of their 

 structure, and families by their forms. I would also 

 further remark, that there is one question relating to the 

 form of animals which I have not touched upon here, and 

 which it is still more important to consider in the study 

 of plants, namely, the mode of association of individuals 



