94 bulletin: museltvi of comparative zoology. 



lateral part {spi. I. 3), which divides at once into several small rami, 

 innervating the muscles immediately adjacent and caudad to it. 



The dorsal ramus {spi. d. 3) divides into two branches; the one, 

 wholly motor (Plate 2, fig. 6), passes dorso-mesad to supply the muscle 

 lying against the neural arch; the other, a mixed sensory-motor, re- 

 ceives a communicating branch from the dorsal ramus of the second 

 spinal nerve and innervates the most dorsal portion of the longissimus 

 muscle anterior to the general position of the nerve as a whole (Plates 2, 

 3, figs. 4, 6). The cutaneous part passes through this muscle to the 

 skin, where it divides to be distributed both dorsally and laterally; 

 but like the motor part its field of distribution is chiefly anterior to 

 the nerve. 



The ventral ramus is a combination of the ventral divisions of the 

 motor and sensory components. The mixed branch thus formed 

 passes ventro-laterad between the m. longissimus colli and spinalis 

 colli (Plate 7, fig. 24, spi. v.S). It crosses on the dorsal side of ramus 

 visceralis X and the sympathetic trunk (Plate 2, fig. 4). Between 

 the muscles above mentioned it receives a reinforcement of motor 

 fibers from the ventral ramus of the second spinal nerve (Plate 7, 

 fig. 24, spi. v. 2), about half of whose fibers join the third spinal for 

 distribution, the rest continuing caudad. This combined ^•entral 

 ramus now passes laterad into m. capiti-cleido-episternalis. Here the 

 motor elements leave the main ramus to supply this muscle in both 

 caudal and rostral directions. (The motor fibers appearing in m. 

 depressor mandibulae adjacent to this region are found by dissection 

 to come from ramus hyoideus VII). The cutaneous components 

 also divide into two branches (Plate 2, fig. 4). One passes ventrad 

 between mm. cucullaris and depressor mandibulae, the other passes 

 directly through the latter muscle to a position just lateral to the 

 main trunk of nerve XII, where it turns cephalad to be distributed 

 to the integument along the ventro-lateral region of the neck and 

 throat (Plates 3, 7, figs. 6, 23, spi. v. 3). 



A variation in the ganglion of the third spinal nerve deserves men- 

 tion in this connection. This is indicated in the plotting and consists 

 of a small group of ganglion cells on the dorsal sensory ramus not far 

 from the main ganglion. In the labelling a dotted line runs to this as 

 well as to the main ganglion from the letters {gn. spi. 3). In other 

 series of sections of Anolis this small ganglion did not appear. The 

 size of its cells and its nerve connections do not suggest for it a sym- 

 pathetic function, the cells being in every way similar to spinal gan- 

 glion cells, their position probably being due to a migration of 

 some of these cells from the main ganglion. 



