338 GENERAL ZOOLOGY 



vertebral column consists of nine vertebrae, terminated by a 

 long bone called the urostyle (tail bone). 



The bones of the arms are attached to a shoulder girdle 

 consisting of the shoulder blades, or scapulse, two coracoids, 

 and two collar bones, or clavicles. A broad breastbone 

 (sternum) extends a short distance along the median ven- 

 tral line. Each of the anterior limbs contains one bone in 

 the upper arm, called the humerus ; one bone in the fore- 

 arm, composed of two bones united, ■ — the radius and ulna ; 

 six bones in the wrist region, or carpus ; four complete sets 

 of bones in the palm (metacarpals) ; and four complete sets 

 of finger bones (phalanges). The metacarpals and phal- 

 anges of the inner digit are rudimentary. 



The leg bones are attached to the vertebral column by 

 means of a hip or pelvic girdle, of peculiar shape. The skele- 

 ton of each leg consists of one bone in the upper leg, the 

 femur ; one bone in the lower leg, formed from two bones 

 united, the tibia and fibula ; five bones in the ankle region, 

 or tarsus ; and five complete sets of phalanges. A sixth rudi- 

 mentary digit is also present, consisting of one metacarpal 

 bone and two phalanges. 



The Nervous and Muscular Systems. The nervous system 

 is similar in general plan to that of the perch. The brain has 

 large cerebral hemispheres (cerebrum, Fig. 173), each of 

 which is prolonged anteriorly into an olfactory lobe. The 

 optic lobes are also large, but the cerebellum is small. Be- 

 hind the cerebellum is the medulla oblongata, at the posterior 

 end of which the spinal cord arises. The nerves are not shown 

 in the dissection. The muscles are arranged in bands, or 

 spindle-shaped masses, instead of in segments, and the frog 

 is capable of much more complex movements than the perch. 



The Reproductive System. The spermaries of the male 

 frog (Fig. 173) are bean-shaped bodies lying beneath the 

 kidneys, to which they are attached. The ovaries of the 



