Family of Laniadec. SOI 



of by sale), and by the labours of public collectors sent to all 

 parts of the world. With such enviable means, therefore, of 

 advancing the philosophy of the science, let us hope they will 

 bestow less attention upon species; and more on the study of affini- 

 ties, and those general laws of Nature which claim the primary 

 attention of a philosophic mind. 



I must therefore be understood, in the following remarks, as 

 speaking only of the American birds ; for I have not yet seen any 

 of the Indian Myotherce* of M. Temminck, nor am I acquainted 

 with any species either from Africa or Australasia. 



The type of Thamnophilus may be represented by the Laniusi 

 doliatus of Linnaeus ; and the characters by which it is separated 

 from the African genus Malaconolus, have already been noticed. 

 The bills of the larger species are strong and powerful, particu- 

 larly the under mandible, which is deeply notched, and the gonix 

 is considerably curved : it i9 in this organ that all the strength of 

 the bird is concentrated; for the wings are short and rounded, the 

 tail cuneated, narrow and weak, and the tarsi and claws much 

 weaker than in Malaconotus. As we descend to the smaller 

 species, the strength of the bill, and the size of the bird, are pro- 

 portionably diminished ; yet without any change of structure. It 

 is at this stage of our progression that I propose to fix the limits 

 of Thamnophilus, and pass into the genus Formicivora : here the 

 bill is no longer robust; but narrow, slender, and more cylin- 

 drical ; the under mandible weak, and the gonix nearly strait ; 

 the tail of some species is even longer and more cuneated than in 

 the last group ; but, as we proceed in the series of species, it 

 becomes gradually shorter, while the tarsi are proportionably 

 lengthened, until we come to a third type of form, wherein the 



* M. Temminck has given a very extensive latitude to this genus, which 

 was originally instituted by Illiger, from the Turdus colma (PI. Enl. 821), a 

 South American bird. In the Manuel a" Ornithologie, it is stated, " Toutes leg 

 especes sont de V Amerique Meridionale;" nevertheless, we find that Myothera 

 capistrata and M. melanotkorax of the Planches coloriees (PI. 185) are both natives 

 of Java. As the original genus has thus been so much changed, in order to 

 contain other approximatory types, it is here necessary, for the sake of per- 

 spicuity, to apply the name only in reference to the type originally proposed 

 by Illiger. 



