496 Mr. N. A. Vicors on the Natural Affinities 
The former groups, however, still retain their relation to the typi- 
cal families of their own order, by frequenting for the most part 
the inland lakes or rivers. ‘The birds upon which we now enter 
become more decidedly pelagic in their food and habits; their 
typical station in nature appears included within the limits of the 
ocean, and their ** business is in the great waters." We may have 
remarked in the course of this inquiry, that the typical families of 
an aberrant tribe or order are less perfect in their general con- 
formation, than the families of the same group which deviate from 
the type. This is necessarily the case. The tribe or order is itself 
aberrant, and deviates from the more perfect structure of the con- 
terminous tribes or orders that are typical in the more compre- 
hensive division under which all are classed. "The typical subdi- 
visions of this aberrant tribe or order will consequently be those 
which carry this deficiency to the extreme. In reference then to 
their own division, the typical perfection of such aberrant groups 
will consist, if I may so express myself, in their general imperfec- 
tion—their strength will be in their weakness. To instance this 
point we may refer to the order of Insessores, where the typi- 
cal families of the two most aberrant tribes, the Tenuirostres and 
the Fissirostres, exhibit less general perfection of structure than 
the families which are less typical. In the former instance the 
Cinnyridæ and Trochilide, the types of the tribe, evince in their 
general organization a considerable degree of feebleness, both in 
their bills and legs, in comparison with the strength displayed 
in many groups of the aberrant Meliphagide and Nectariniade. 
We may observe the same character in the tribe of Fissirostres 
also, where the general weakness of the structure of the typical 
Hirundinide and Caprimulgide forms a striking contrast with 
the comparative strength and robustness of many species of the 
remoter groups Todide, Meropide, and Halcyonide. The pre- 
valence of this principle in the groups that have already come 
cO before 
