874 r»R. C. F. SONNTAG ON THE VISCERAL ANATOMY 



In the first type, Avhich is present in both Polypi"otodonts and 

 Diprotodonts. they are fused to form vago-sympathetic cords. 

 In the second form, which is found onlj^ in Diprotodonts, they 

 are connected by a variable number of communicating branches. 

 In no Marsupial did I find both types present in the neck as I 

 observed them in Tamanchia tetradactyla and Lutra maculicoilis. 

 These forms were present as follows in my specimens : — 



Type 1 : — Metachirus opossu7n, Bidelphys azarce, Didelphys 

 marsiipialis, Philander laniger, Dasyurus vwer7-inus, iSarcojohilus 

 harrisi, Ferameles obesula, Phascolarctos cioieretcs, Trichosurus 

 vuljjecula, and Petatoi'us scuoreus. 



Type 2 : — Dendrolagus ursinus, Macropits giganteus, Macro2nhs 

 hennetti, Pseudochirns pereyrioius, and ^pyprymntis rufesceris. 



The course of the vagi from the base of the skull to the point 

 where they reach the cesophagus in the posterior part of the 

 thorax has already been described in my paper on the Koala (15), 

 but the branches vary considerably. 



The vagus (V) and hypoglossal (XII) nerves are fused in 

 Phascola7'ctos cinereus, but branches of communication run 

 between them in other Marsupials. 



In Dendrolagus ursinus the pharyngeal (a) and superior laayn- 

 geal (b) nerves are given ofl^ from the sjanjjathetic on the right 

 side, but from the vagus on the left. The cord giving off the 

 right nerves supplies the submaxillary glands (s.g.n), and 

 possesses a ganglion (g') ; it probably contains vagus fibres. 



The vagus and sympathetic communicate. In the first type 

 branches run between the vagus and superior cervical ganglion 

 {s.c.g). In the second type there are several branches of com- 

 munication (c') throughout the neck as well. 



At the root of the neck the right vagus gives oft" its recurrent 

 branch [d), and the vago-sympathetic cord is resolved again into 

 its component vagus (v) and sympathetic (s) elements. I observed 

 no communications between the right and left recurrent laryn- 

 geal nerves, but the right nerve and sympathetic cord com- 

 municated. 



Cardiac Nerves : — In type 1 the vagus transmits sympathetic 

 cardiac nerves, but in type 2 (text-fig. 79) the cardiac branches of 

 the vagus (/) and sympathetic are separate throughout. And the 

 cardiTiC branches of the sj^mpathetic (c.b.s) come fi-om the middle 

 ganglion or main cord, but never from the superior ganglion. 

 The cardiac and pulmonary plexuses have well-marked ganglia in 

 Dendrolagus iirsinus, and that species has large tracheal and 

 resophageal jolexuses. 



The Posterior Thoracic Parts of the Vagi : — Id the Koala, as in 

 some reptiles, birds, and Man (Wirsung's case), they are fused to 

 forma combined trunk; but the trunk of the Koala is not 

 I'esolved again into the two vagi. And many gasti'ic nerves are 

 given oft" in the thorax. 



In Metachirus opossum the left vagus runs along the ventral 

 surface of the cesophagus. It gives off" a branch which accom- 



