THE RAMUS LATERALIS VAGI. 121 



from the ramulus in about the middle of its course and 

 turn caudad, anastomosing in the dorsal muscle with the 

 branch of the next ramulus, about to be described, which 

 joins the r. accessorius lateralis (see Fig. 4). 



J. — T/ie Second Lateral Ramulus. 



This follows close upon the preceding ramulus, and like 

 it contains both coarse and fine fibres. It runs dorsad and 

 in the dorsal muscles divides at once, one portion turning 

 cephalad, the other caudad. At the point of division it 

 effects an anastomosis with the ramus medius c of the first 

 spinal nerve, as described in the account of that nerve, 

 some of the latter fibres going out to the skin in the 

 vicinity of the lateral line organ supplied by this ramulus. 

 The fibres of both of these divisions are chiefly of medium 

 size, those for the lateral line organ being from 4 to 6 

 micra, the others from i to 4. The portion running ceph- 

 alad receives the minute anastomosing twig from the first 

 ramulus, mentioned above, and then, while still within 

 the dorsal musculature, divides. One twig, of fine fibres, 

 turns dorsad and caudad to a naked cutaneous sense 

 organ resembling the one innervated from the r. supra- 

 temporalis and situated a short distance dorsad and 

 cephalad of the open caudal end of the post-occipital 

 lateral line canal (735). The other twig {a. r. VII . j, 

 Fig. 4) runs dorsad, and then caudad under the skin and 

 joins the r. lateralis accessorius (830, Fig. 3). These 

 fibres, though slightly coarser than those of the other 

 twig, are still finer than any proper lateralis fibres. 



The portion of the second ramulus which is directed 

 caudad, also divides into two twigs. One of these sup- 

 plies the second post-occipital organ of the lateral line, 

 which is the first free organ of the trunk. The other 



