RASORES. 403 



widely different from what we behold in the former orders ; 

 the toes being short, and strengthened by a membrane con- 

 necting them at the base ; with the hind toe either entirely 

 wanting, or but imperfectly developed. Where this latter 

 does exist, it is not articulated upon the same plane as the 

 other toes (as we have seen it in the former orders), but up- 

 on the tarsus, at a height greater or less, according to the 

 cursorial powers of the species. 



The five prominent divisions or families, which seem to 

 compose the circle of this order, are the Columbidce, Phasia- 

 nidiE, Tetraonidce, StruthionklcB, and CracidcB, all (except 

 the fourth and fifth) connected together by a beautiful chain 

 of affinities. By the Columbidae, whose feet, in some of its 

 component groups, approach nearest in structure to those of 

 the preceding orders (but whose anatomy and general habits 

 class them among the typical Rasores), the necessary con- 

 nection is sustained with the Insessores. This conformation 

 of the feet, however, we see decrease as the species approach 

 gradually nearer in form and habits to the true gallinaceous 

 birds, exemplified in the Great-crowned Pigeon {Lophyrus), 

 the Nicobar Pigeon, &c. The near connection of the Phasiani- 

 dae (or perhaps, as it ought to be called, the PavonidcB) with 

 the Tetraonidae, is too apparent to require comment. The 

 passage from the latter family to the Struthionidae seems to be 

 effected through the genus Tinamus, and other nearly allied 

 birds ; where the feet are tridactyle, and the bill approaches 

 very closely in form to that of the American Rhea, a bird 

 almost equalling the Ostrich in size, and, like it, deprived of 

 the power of flight. The immediate bond of union between 

 the Struthious birds and the Cracidae is not at present so 

 apparent, requiring the intervention of some connectino- 

 form (perhaps the Didus, or Dodo, now supposed to be ex- 

 tinct) ; but the affinity of the latter group to the Columbidse, 

 with which the circle commenced, is shewn in the structure 

 of the feet, and in other particulars of form, as well as in 

 habits, of certain species of the genera Penelope, Ortalida, 



c c2 



