S38 PRACTICAL AND SCIENTIFIC ZOOLOGY. 



SHRIKES. Distinguishing Characters. TYPES OF BIRDS. 



} f The most rapacious of all} 



_, . , \-Lanius. < the perching birds ; conse- J- Raptorial. 



Typical. j quentlythe 3 



} f Glossy plumage, great tails,} 



, ~" . , >Edolius. < crested heads ; conse- J. Rasorial. 



Sub-typical, j ^ quently the 3 



C C Small short feet, great heads, } 



I Tyrannus. < broad flat bills, dive in the Natatorial. 



C water*; consequently the 3 



3. J /vUtMtiu ' f Live entirely upon soft sub- 7 



Aberrant } ^blepyrus. ^ stances; consequently thej 



Inferior only to the shrikes, } 

 l > 



I Thamnophilus. \ in not having raptorial > Insessorial. 

 L t claws; consequently the 3 



Here^ then, it is seen, that in this supposed circle the 

 Rasorial type of form is followed by the Natatorial, and 

 not, as in all other birds, by the Grallatorial ; while 

 the genus Thamnophilus, whose structure, being only in- 

 ferior to that of Lanius, shows it to be one of the typical 

 groups, is placed in the aberrant division. The series 

 of variation, in short, in the circle we are now testing, 

 turns out to be different from that in all other groups 

 of birds, and it therefore cannot be the true one. 



(41 6.) Our imaginary circle, therefore, not being 

 able to stand the test supplied by the theory of definite 

 variation, we have to retrace our steps, and ascertain 

 whether an equally good circle cannot be formed 

 by ..placing these divisions in a different series. This 

 we find can be done, the new circle is just as 

 complete as the old, and we then compare it with the 

 types of variation (as above specified), as follows : 



2 } f The most rapacious of all the} 



Typical YLaniut. -s perching birds; therefore S- Raptorial, 



2 r Inferior only to the last, bill } 



Sub tvnieal f Thamnophilus. < conic-shaped, claws not V Insessorial. 

 * > L raptorial f therefore the 3 



If Glossy plumage, great tails, } 

 Edolius. < crested heads, gregarious > Rasorial. 



C habits; therefore the 3 



Aberrant 1 *~ PSSStUSS^}***!*- 



( Small short feet, great heads, f 



I Tyrannus. < broad flattened bills, dive > Natatorial. 

 \ (. in the water; therefore the 3 



* See "Wilson's American Ornithology ; also Northern Zoology, vol. ii. 

 p. 136. 



