480 Mr. N. A. Vicors on the Natural Affinities 
the order. Keeping, then, these characteristic peculiarities of 
the Rasores steadily in view, we may draw the conclusion that 
the typical groups will be those which, in reference to external 
character, may be distinguished by the weak conformation of 
the Aallux or hind toe, and the height on which it is articulated 
upon the tarsus. The aberrant groups will in like manner be 
either those whose hind toes are more developed, and articulated 
lower down upon the tarsus, and which thus retain most closely 
the habits of the Perchers; or those which, though they possess 
no hind toe, and thus seem to partake most strongly of the typi- 
cal character of the order, are yet found to deviate from it in the 
length of the tarsus, by which character they lead off to the Wa- 
ders. Following these views of arrangement, we may group the 
Rasores as follows, placing the typical families in the centre* : 
Columbide, Leach. 
Phasianide. 
Tetraonide, Leach. 
Struthionide. 
Cracide. 
I have already observed, when speaking of the affinities which 
connect the orders of Birds together, that the Columbide form the 
passage from the Insessores to the Rasores by their habits of perch- 
ing and their powers of flight. "The hind toe is articulated as in 
the Perchers, and their tarsi are shorter, more particularly in the 
* Or, with reference to their normal and aberrant groups, thus: 
Normal group. 
Halluce brevi, amotá; tarsis f Phasianide. 
precipue calcaratis. . .. | Tetraonide. 
Aberrant group. 
Halluce aut nullo, autplusvel ( Struthionide. 
minus terrz incumbente ; Cracide. 
tarsis nunquam calcaratis. Columbide. 
earlier 
