7 2o THE POPULAR SCIENCE MONTHLY. 



known as the "ploughshare " bone formed by the union of several of 

 its segments into a terminal mass for the support of the rudder-quills 

 and of the oil-gland. Several very marked characteristics are to be 

 seen in the hind-limb, to which, without entering deeply into osteologi- 

 cal details, we may draw attention. Opening into the hollow shafts 

 of the stronger bones a character common to those of the wing and 

 parts of the spine there are to be found small pores, the air-passages 

 by which the air-sacs, themselves extensions of the air-tubes of the 

 lungs, are prolonged into the bones. In the skull also we find numer- 

 ous air-cavities; these, however, are filled, not from the lung air-sys- 

 tem, but from the nasal and ear chambers. No one who has examined 

 the leg-bone, often called the "drumstick" (technically known as the 

 tibia), of a common fowl, can have failed to observe the great ridge, 

 or prominent crest, on the front of its upper extremity, or how easily 

 the pulley-shaped articular surface of its lower end separates off from 

 the shaft in the young bird, especially if the bone has been boiled or 

 macerated for some time in water. This peculiarity vanishes when the 

 fowl attains to its full growth ; but till then the separation remains, as 

 if to assert the right of the extremity to be considered, what in reality 

 it is, a separate and distinct bone, the sole representative of a colony 

 of ossicles (corresponding to the bones of the heel in the human foot) 

 once existing in its grandsires at this spct, which for reasons of expe- 

 diency has here coalesced with its long neighbor. On its outer side 

 the leg-bone is always accompanied by a very slender bone, known as 

 the fibula, attached only at its upper end, tapering gradually to a point 

 about the middle of its fellow. Lastly, to the leg-bone immediately 

 succeeds the hock-bone, the beautiful conformation of whose lower end 

 into the resemblance of a triple pulley, for the articulation of the toes, 

 is a mark by which we can unhesitatingly say that it belonged to a bird. 

 Bearing in mind these peculiarities, for whose detection no very 

 deep scrutiny is required, which are but a few, yet sufficient for our 

 present purpose, of the more striking characteristics to which the mem- 

 bers of the Avian family more or less closely conform, we shall now for 

 a little turn our attention to that other division of the animal kingdom 

 with which we have in the title of this article contrasted the bird. 



The reptiles are a wonderfully interesting group on account not only 

 of the marvelous variety of their habits and modes of life, but also of 

 their manifold diversity of form. Our country, in common with the 

 rest of Northern Europe, can claim to be the habitat of but few exam- 

 ples of this tribe, whose home is under warmer latitudes ; and conse- 

 quently only limited opportunities present themselves to the European 

 student for becoming acquainted with their habits and animated forms, 

 unless he happens to live within reach of the menageries of the Zoologi- 

 cal Societies of London, Berlin, Paris, or Amsterdam ; those who are 

 unfortunately distant from such interesting educational centres must 



