GENERAL BIOLOGY 



III. MUSEUM SPECIMENS. 



Observe in the Museum, south wing, numerous preparations of 

 organ systems of different vertebrates, and compare them with 

 corresponding organ systems of the frog. 



B. THE SKELETON. 



In connection with a dried prepared skeleton, study a fresh 

 skeleton, boiled for a few minutes after removing the skin and 

 viscera. 



I. GENERAL ARRANGEMENT OF PARTS OF THE SKELETON. 



a. The main axis consists of the vertebral column continued 

 anteriorly as the central part (brain case) of the skull. 



b. Connected with the main axis are the supporting parts of 

 the appendages, and the lateral parts of the skull. 



1. The anterior appendages consist of a free limb (containing 

 a humerus, radio-ulna, carpus and digits, supported by a shoulder 

 girdle or pectoral arch. 



2. The posterior appendages consist of a free limb (containing 

 a femur, tibio- fibula, tarsus and digits) connected with the spinal 

 column by the pelvic girdle. 



C. HISTOLOGY. 



I. EPITHELIUM. 



a. Columnar epithelium: Gently scrape the inner surface of a 

 frog's intestine that has been preserved in Miiller's fluid. The 

 fragments removed, under a high power, are seen to be composed 

 of elongated cells each with a nucleus and having one end more 

 pointed than the other. 



b. Ciliated epithelium: Cut off a bit of the mucous membrane 

 from the tongue or roof of the mouth of a freshly killed frog, 

 mount in physiological salt solution and examine under a high 

 power. Note the appearance on the free edge due to the cilia ; as the 

 cilia become less active individual ones can be distinguished. Scrape 

 off some of the epithelium and examine under a high power in 

 physiological salt solution ; note the shape of the individual cells 

 with cilia at one end. 



Draw both kinds of epithelium. 



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