A TURTLE 141 



Note the exact point where the ureter joins the kidney. Slit open 

 the entire cloaca and note the mouths of the ureters and the 

 genital ducts. Observe the exact relation of the ureters to the 

 urinary bladder. 



Exercise 14. Make a drawing of the urinary organs. 



Remove the lungs and the urogenital organs from the body. 

 Observe the great retractor muscles of the head and neck by means 

 of which these structures may be drawn under the shell. Observe 

 those of the pelvis. 



The Nervous System. This system is made up of the following 

 parts : ( 1 ) the central nervous system, consisting of the brain and 

 the spinal cord; (2) the peripheral nervous system, consisting of 

 (a) the paired cranial and spinal nerves which spring from the 

 central nervous system and join it with the sense organs, muscles, 

 and other organs, and (b) the sympathetic nervous system, which 

 lies, for the most part, in the body cavity and is connected by 

 branches with the spinal nerves and with the various viscera ; and 

 (3) the organs of special sense. 



We shall study first the spinal nerves and the sympathetic nerv- 

 ous system. The spinal nerves spring from the spinal cord and 

 pass through the intervertebral foramina of the spinal column to 

 the muscles of the neck and trunk and the inner surface of the 

 carapace. The sympathetic nervous system consists of a pair of 

 longitudinal nerves lying one on each side of the spinal column, 

 each nerve containing ganglia at intervals corresponding to the 

 spinal nerves. Branch nerves connect each ganglion with a spinal 

 nerve, and others pass to the various viscera. 



Note the spinal nerves, which extend as white threads across the 

 inner surface of the carapace from the vertebral column to its 

 outer border. Six or seven pairs will be seen. Each nerve consists 

 of two main strands lying side by side. The spinal nerves of the 

 neck, with the exception of the first pair, may be seen by pushing 

 aside the retractor muscles on the neck. The four or five posterior 

 pairs of cervical nerves form, together with a branch from the first 

 spinal nerve of the trunk, the brachial plexus, a network of nerves 

 from which arise the nerves which supply the foreleg. 



