1G8 FOURTH REPORT — 1834. 



families. Blainville's arrangement of this class* is grounded 

 upon the form of the sternum and its appendages {clavicle and 

 OS fur cat ur ins), according to a plan first developed in a memoir 

 read to the Institute in 1812. At the same time, for the sake of 

 convenience, its author has had recourse to the usual external 

 characters for distinguishing the groups. As the sternum gives 

 attachment to the principal muscles of flight, and thereby ne- 

 cessarily exercises a certain influence over the ceconomy, it may 

 assist in determining many natural affinities which would other- 

 wise escape us. Hence Blainville's system deserves to be i-e- 

 garded, although we may not be disposed to adopt it entirely. 

 One of its chief peculiarities consists in the forming a distinct 

 order of the Parrots, which stand first in the arrangement. 

 Blainville thinks that not only the form of the sternum, but the 

 whole organization and habits of these birds justify this step. 

 With the rest of the Scaiisores, which are separated from the 

 above by the intervention of the Birds of Prey, he associates the 

 Syndactyli and Capritnulgidce, groups not referred by Cuvier 

 to this order. He has also made distinct orders of the Pigeons 

 and Ostriches. His other orders nearly coincide with those of 

 the R^gne Anim. Although not immediately following in point 

 of time, I may here notice an elaborate memoir on the sternum 

 of birds by M. L'Herminier, published, in 1827, in the Ann. de 

 la Soc. Linn, de Paris f, in which he has endeavoured to draw 

 the attention of naturalists afresh to the great importance of this 

 part. He has studied its structure in a large number of species, 

 and founded upon it a new classification entirely different from 

 all former ones excepting that of Blainville. He divides birds 

 into two subclasses ; the first comprises all those io which the 

 sternum is constantly furnished with a keel, and is distributed 

 into thirty-three families ; the second forms but a single family, 

 containing the Ostrich, Cassuary, and a few others, in which the 

 keel is always wanting. M. L'Herminier thinks that the birds 

 just mentioned conduct to the Reptiles, and not to the 3Iam- 

 malia as is generally supposed. In 1823 appeared Mr. Vigors's 

 *' Observations on the natural Affinities connecting the Orders 

 and Families of Birds;}:," to which allusion has been already made, 

 as containing an application of Mr. MacLeay's principles. His 

 primary divisions are the same as Cuvier's, excepting that he 

 sinks the order Scansoi'es, which he considers as only a subor- 

 dinate group of his order Insessores, which name he has sub- 

 stituted for that of Passeres. The names adopted for his other 



• Priiicipes, &c., tab. 4. f torn. v. p. 3 — 93. 



J Linn. Trans., vol. xiv. p. 395. 



