236 VERTEBRATES. 



i 



meeting the hemispheres in front, and overlapping the 

 optic lobes at each side. 



6. A large medulla, covered in front by the cerebellum, 

 and narrowed posteriorly into the spinal cord. 



On the ventral surface note the crossing of the optic 

 nerves (optic cJiiasma), and just behind this, on the median 

 line, a small process (the infundibulum), which was con- 

 nected with the pituitary body before the removal of the 

 brain. 



The sparrow is a representative of the vertebrate class 

 Aves (or birds). 



Other Birds. If material is at hand, and if time will 

 permit, the further study of this interesting and important 

 group is recommended. A hawk, a duck, a woodpecker, 

 and a snipe are in most places obtainable ; and these four 

 are mentioned for further study, because they illustrate 

 common types of bird structure. It will be interesting to 

 compare a number of birds as to the following points of 

 structure, noting in each case the exact adaptation of each 

 structural peculiarity to the life and habits of the bird in 

 which it is found. Note : 



1. The relative size and proportions of body, wings, and 

 tail. 



2. The character of the plumage. 



3. The shape, size, and strength of leak and claws. 



4. The number, insertion, and direction of the toes, and 

 the amount of webbing between them. 



5. The length and position of the neck and of the legs. 



6. The size and position of the eyes. 

 In the field, note : 



1. Their haunts. 



2. Their food, and manner of obtaining it. 



3. Their flight . Learn to know a bird by this alone. 

 The rapid, whistling flight of some ducks ; the cycloid 



