78 AVES. 



SUBGENUS ANAS, Meyer. Duck. 



Beak widened and much flattened towards the end ; legs 

 very short ; neck moderate. Some species have the thumb 

 bordered with a membrane, others have not. 



GENUS FULIGULA, Leach. 



Beak broad and flat. The Canvass-back and Red-neck 

 belong to this genus. 



GENUS MERGUS. 



Beak thin, cylindrical, much crooked at its extremity; 

 mandibles with sharp teeth directed backwards ; nostrils per- 

 forated. 



REPTILIA. 



Reptilia are oviparous Vertebrata, with an incomplete cir- 

 culation and diminished respiration, organized for creeping. 



On each contraction of the heart in Reptiles, only a part of 

 the blood received from the system is thrown into the lungs, 

 and therefore only that portion is exposed to the action of the 

 atmosphere. It results from this that the respiration is less 

 than in the preceding divisions, consequently the heat of the 

 blood is less, and they are called cold-blooded animals ; their 

 muscular energy is less ; digestion slower ; sensations more 

 obtuse ; and in cold climates they pass the winter in a state 

 of torpor. 



The brain is small in proportion to the size of the animals, 

 and their sensations do not appear to be referred to the brain 

 as a common centre, since they live and move after the loss 

 of the brain and even after the removal of the head. 



The external covering of the body is composed of scales or 

 naked skin, as on account of their blood being cold they do 

 not require to be protected against the loss of temperature. 

 Their eggs are not hatched by the parents, but generally by 

 the influence of solar heat. 



