BO A MANUAL OF ZOOLOGY 



the diameter of the leg vary greatly throughout its length? 

 Note the upper arm, brachium; the forearm, the antibra- 

 chium; the hand, the manus. What is the relative propor- 

 tion of each of thesg parts to the length of the leg? How 

 many digits on the manus? Do you find a thumb, 

 Pollex? Note the number of joints in each digit. Would 

 you judge these legs to be good organs of locomotion in 

 the water? Why? In the posterior legs note the thigh, leg, 

 crus, and foot. How do these parts compare with those 

 of the anterior leg? Do you find a great toe, the hall ex'/ 

 Make a sketch of the frog, side view as seen alive. 



INTERNAL ANATOMY— The Skeleton. Study skele- 

 ton prepared in Wickersheimer's fluid. Note the axial 

 skeleton, consisting of skull; vertebral column; appendi- 

 cular skeleton, and limb girdles: anterior, the pectoral 

 girdle; posterior, the pelvic girdle. 



The Vertebral Column — Of how many parts does it 

 consist? What is the general shape of each part? How 

 does the urostyle compare In shape and structure with 

 the anterior part of the vertebral column? Near the an- 

 terior end of the urostyle -find two openings, foramina for 

 nerves to enter. Draw the urostyle from the side. The an- 

 terior part of the axial skeleton is made up of parts call- 

 ed vertebrae. How many do you find? Stud^ thein for 

 differences. Examine one, the third as a type, and note 

 that it is a bony ring with several projections. Note 

 the ventral portion, the body. What is its structure? On 

 the dorsal side is the neural arch. Note the shape as 3een 

 from the end. Find the spinous process. On dorsal side 

 of each, the transverse process on the side of the neural 

 arch. Note their shape, size, and direction. Find the an- 

 terior and the posterior articular processes. Why are 

 they called articular processes? Are there any ribs? Draw 

 end and sid& view of a vertebra. Compare carefully the 

 first vertebra, the atlas, and the last, the sacrum, with 

 the one just studied. Can you find all the processes men- 

 tioned above? Do you find any modifications of these 

 processes? Find the odontoid process, a projection on 

 the body of the atlas. The intervertebral foramina will 

 be noticed, by studying the entire column, on the lateral 

 area just below the articular process. Note the direction 



