12 THE AMERICAN MONTHLY [Jan. 



ing tissues and display the eye-ball; recognize the various 

 parts and compare them with tliose of the smelt. Cut 

 away the skin and muscle Ironi the dorsnl hinder sur.'ace 

 of the he;i<l. You will thus be jible. to had tlie bony brain- 

 case in the middle aud hinder part, and on either side be- 

 hind a lateral bony extension lodging the car-capsule. 

 Fi'o Q tliis the boue.s of the appjr jaw run forward tj meet 

 in the middle line in front. 



The lower jaw articulates with the upper near the 

 ears. The r^'?' does not show externally in the salamander 

 but it does in the frog in the form of a rounded piece the 

 tympanum. Cut into the ear capsule and you will find 

 some of the parts of the ear, for a detailed (lesciii)tion of 

 which a more extended woik must be consulted. Open 

 the mouth widely and examine its interior. Are there any 

 teeth? If so where and of what form and number? 

 Note the large and fleshy tongue^ what is its shape and 

 mode of attachment? The naiTow nlit back of the tongue 

 is \\\.% glottis it leads into the wind i>ipe. Note at the 

 back of the mouth chamber the opening of the gullet; as 

 in the fish there is no distinct throat: The hinder part of 

 the mouth chamber is the equivalent of the throat; and 

 in younger specimens its walls are i)erforated and allow 

 water to pass out over gills which at that time are j)re- 

 sent and ustd for resi)iration as in the fish. (In some 

 urodeles the gills and fius persist through life e. g., 

 Necturus). 



3. The Brain. — Cut away the cranial bones dorsally, 

 noting that they form a thin layer covering a caj)snle of 

 cartilage which immediately encloses the brain, lu re- 

 moving the bones to display the bruin be very careful 

 not to injure the latter. The situation of the braia 

 should be first noted in the hinder part of the head; its 

 relation to the sense organs should be ascertained and 

 the facts recorded. Study the different principal parts 



