876 DR. C. F. SONNTAG ON THE VISCERAL ANATOMY 



lower Yertebrata. In Metacliims opossum and Perameles ohesula 

 the left vagus ends in the ventral wall of the stomach, and the 

 right one gives branches to the stomach and ends in the solar 

 plexus. In the third type, which is exemplified by Dendrolagus 

 ursinus (text-fig. 79 B), the main masses of the vagi end in the 

 stomach, and branches of communication run to the solar plexus. 

 Niunerous bi-anches (g.jy.n) run to the special gastric gland. 



I never observed any other mode of termination in the 

 Mammalia, but the branches of communication between the vagi 

 and the abdominal sympathetic plexus are more numerous in 

 some of the Eutheria. 



The Cervical Sympathetic : — The arrangement in animals with 

 the first type is figured in my paper on the Koala (15), and that 

 in the second type is shown in text-fig. 78. 



The superior cervical ganglion (S.C.G) is always present ; the 

 inferior one is frequently present, but the middle one (M.C.G) is 

 very variable. It is well-marked in Dendrolagus ursinus, but 

 absent in yEpy2)rymmis rtifescens. In a pouch specimen of 

 Macrojms giganteus it appears as a slight increase in the diameter 

 of the nerve. When both middle ganglia are present one may 

 be minute and give oflf no branches. The branches of the cervical 

 sympathetic are : — 



1. Communicating to the cervical plexuses, vagi, and right 

 recurrent laryngeal nerve. 



2. Branches accompanying the common carotid {a.h), sub- 

 clavian, and vertebral arteries. 



3. Cardiac nerves (c.b.s.) which arise from the middle or inferior 

 ganglia or main cords themselves. 



I was unable to trace the filaments accompanying the vertebral 

 aiieries to the brain. In some higher Mammals they can be 

 traced nearly to the interpeduncular space. 



The sympathetic cords terminate in one of three ways. They 

 may end in the solar plexus and giveofi" no branches to the aortic 

 plexus; and in this and the next form no splanchnic nerves are 

 present. In the second type the main mass of the sympathetic 

 ends in the solar plexus, but sends a small communication branch 

 to the aortic jolexus. In the third type, Avhich is the com- 

 monest, the cords run back to the sacral region, and splanchnic 

 nerves are present. 



It has been shown by Yolkmann, Bidder, and others that the 

 sympathetic becomes included more and more in the vagus as we 

 descend the vertebrate scale, and I believe that the form in 

 which they are fused in the neck is more primitive than that in 

 which they are separate. The nerves are fused in the neck in 

 Ornithorhynchus (Knox). 



In Dendrolagus iirsimis the phrenic nerves bifurcate beyond 

 the roots of the lungs, and the halves pass to the ventral and 

 dorsal parts of the diaphragm. The nerve to the omo-hyoid 

 comes from the cervical plexus, and has no connection with the 

 hypoglossal nerve as in Petrogale xanthopus. 



