REVIEWS. 151 
ness with which he has gone over the ground. To state the reasons which 
devoted to the subject here. We may add, however, that the separation 
of birds into Altrices and Precoces, though based chiefly upon di HK 
distin — is a classification that appears to separate the bi da in 
two natural, primary groups, —2a division wholly ignored however ia 
Li Mesi and rejected by Dr. Coues. In regard to the boss which 
lies at the foundation of ek division, the latter author himself admits 
that **as Mediae testimony in the formation of orders and location of 
fu 
probably be decided by reference to it." As he says further, ** It draws 
sharp, if here and there a broken [?], line between Galline sns apice 
It separates, with opem herons and their allies from oth ralle. 
It goes some way in distinguishing lamellirostral from other paeng, 
and other inc of its application mig e cited." The exception 
doubtless referred to in the italicized portion of the above extract occurs 
in the Pygopodes, which is an (artificial 2 mete of altricial and præ- 
cocial types. On this basis the **ord gopodes would be divided, 
the altricial Alcide and Peste Ae associated with the Altrices as 
he est members of that series, and the Colymbide and Podicipide 
s 
the Steganopodes and the altricial Pygopodes. 'The Lamellirostres would 
head the proecocial or lower series, followed = the Colymbide and Podi- 
cipide 
Finally, a word in regard to one or two other systems. Birds, more 
other class of po uui being fitted to live more or less ex- 
cus cal in either the air, the water, or on the land, the duties of repro- 
duction alone ae ni ‘eae indispensable to some of them, different 
odes and degrees of locomotion, with corresponding differentiations of 
the locomotive organs, are required to adapt them to their several modes 
of life. But facts go to prove that such modifications have not neces- 
verse of all this, till gradually the wings become functionally abortive, 
and the sternum a smooth buckler. An exclusively walking or swimming 
bird (a non-flying bird), with a largely developed sternal crest would be ' 
an anomaly in nature; and a flying bird, especially one preéminently 
strong of wing, without a highly produced sternal crest, would be appar- 
ently an impossibility. Hence the propriety of founding subclasses prin- 
cipally upon the presence or absence of such a sternal character — as it is 
well known has been done — seems at least highly questionable. Again, 
