SYMPATHETIC OF EEPTILES. 321 



by a cross branch : they then send nerves which join the gastric 

 branches of the vagi, in order to form or join a splanchnic ganglion 

 and plexus on the mesenteric artery, from which plexus branches 

 are sent to the intestines, pancreas, and spleen. The sympathetic 

 trunks are continued on each side of the aorta, along the back of 

 the abdomen, into the hremal canal ; communicate, in their course, 

 with the ventral branches of each of the spinal nerves ; supply by 

 filaments, usually accompanying the arteries, the kidneys, the 

 generative glands, and the urinary bladder, where this exists ; 

 and often, finally, blend together into a common trunk beneath 

 the tail. Ganglions are sometimes found at the junction of the 

 sympathetic with the fifth, as well as at that with the glosso- 

 pharyngeal and with the vagus, before the great splanchnic is 

 formed : small ganglions are more rarely discernible at the junction 

 of the sympathetic with the spinal nerves. 



The splanchnic ganglion of the Skate is a large fusiform body, 

 of an ash-red colour; the succeeding ganglia on the trunks of 

 the sympathetic are larger and more constant than in Osseous 

 Fishes ; but the intervening chords are semi-transparent. 



59. Sympathetic of Reptiles.- -The trunks of the sympathetic 

 appear, in the Frog, to be formed in a great proportion by con- 

 tributions from or communications with the spinal nerves ; there 

 are, however, slight enlargements at the points of connection, 

 often marked by pigment-cells, in which true ganglion-cells 

 occur, as shown in fig. 212, h. 



In Ophidia the trunks of the sympathetic, conspicuous at the 

 anterior part of the trunk-cavity, on each side the vertebra, 

 bodies, show as little any enlargements where they receive the 

 communicating branches of the spinal nerves as in Batrachia. 

 They slightly diverge as they approach the basis cranii, and are 

 reflected outwards to the vagus, forming a conspicuous ganglion 

 at the junction. From this ganglion the sympathetic is continued 

 forward in a canal of the basisphenoid, and forms a small ganglion 

 with a branch of the second division of the fifth ; it sends fila- 

 ments to the membrane covering the posterior part of the mouth 

 and palate, one of which communicates again with the maxillary 

 nerve. From the last ganglion there proceeds ' another branch 

 forward to form another ganglionic union ' (spheno-palatine) 6 with 

 a branch of the second trunk of the fifth, and from this a branch 

 is sent to the posterior part of the nose, to ramify on the schnei- 

 derian membrane ; other branches are given to the membrane 

 covering the mouth and palate, and one passes forward and com- 

 municates again with a branch of the second trunk of the fifth, 



VOL. I. Y 



