84 TRANSACTIONS OF THE [jAN. 11, 



The above plan, with minor individual variations, is found to 

 prevail throughout the series of cynomorphous monkeys exam- 

 ined. 



The chief point of difference to be noted, in comparison with 

 the usual human arrangement, is the absence of a separate branch 

 from the Second and Third Cervical nerves, constituting the 

 human Occipitalis minor. The deficiency of this nerve is made 

 good to the cutaneous distribution of the lateral occipital and 

 mastoid regions by the large size of the Auricularis magnusand 

 the extensive distribution of the Occipitalis major. 



The communicating twig from the Second Cervical to the Spinal 

 Accessory (Fig. I., 4) may represent the rudiment of the human 

 Lesser Occipital nerve. In Man this nerve is regularly derived 

 from the loop between the Second and Third Cervical nerves, 

 exceptionall}^ entirel}^ from the Second. The Occipitalis minor 

 supplies a communicating branch to the Spinal Accessory. Possi- 

 bly this communicating branch represents the element contrib- 

 uted by the Second Cervical nerve to the Occipitalis minor of the 

 human plexus, the remaining cutaneous branches of the nerve 

 being derived from the Third Cervical. In the Cynomorpha the 

 corresponding brandies remain isolated, not uniting to form a 

 Lesser Occipital nerve. The branch from the Second Cervical 

 nerve (Fig. I., 4), passes directly to the Spinal Accessory as a 

 communicating branch, and the usual cutaneous distribution of 

 the human Lesser Occipital is derived from the Third Cervical 

 through the path of the Auricularis magnus. 



The Occipitalis minor in Man also supplies, in addition to the 

 terminal post-auricular distribution, cutaneous filaments to the 

 narrow dorsal integumentary zone of the cervical plexus, occu- 

 pying the interval between the adjacent margins of the Sterno- 

 cleido-mastoid and Trapezius muscles. These tegumentary 

 branches are either derived from the main nerve, or from a N. 

 occipitalis minor secundus, if such a branch is present. 



In the C^'uomorpha the region in question is occupied by the 

 Levator claviculffi (Omo-cleido-transversarius) or by a Cleido- 

 occipital muscle, a link between the Sterno-cleido-mastoid and 

 Trapezius. The overlying integument receives numerous branches 

 from the Third and Fourth Cervical nerves, for the most part de- 

 rived in common with the muscular branches to the Levator 

 claviculse and the adjacent deeper divisions of the Trapezius. 



The communication of the Third Cervical nerve with the Spinal 

 Accessory in man usually takes place by means of a twig passing 

 to one of the Sterno-mastoid branches of the Accessory. By 

 means of this communication filaments from the Third Cervical 

 nerve pass both peripherally into the Sterno-mastoid branches of 



