i82 THE SALAMANDER 



represents the morphological separation of the pre- and post-gan- 



glionic fibres has not been determined. 



There are two regions of special interest in this section. The first 

 is around the ninth and tenth ganglia from which the middle visceral 

 nerves arise. These run in company with the arteries and are distri- 

 buted to the gonads, spleen, intestine, &c. The details of the visceral 

 ganglia have not been worked out, but it would seem permissible to 

 refer to the tenth ganglion as the coeliac ganglion. Both sides com- 

 municate with one another in this region. The second region of 

 special interest is what Andersson calls the plexus iliacus^ but it seems 

 preferable to use the term renal plexus^ since this avoids any confusion 

 with the spinal nerves. At the point where the post-cardinal veins 

 leave the post caval the sympathetic crosses their dorsal aspect and 

 comes to lie between the kidney and the post-caval vein, always 

 remaining ventral to the aorta. In the male the association of the 

 adrenal bodies and the sympathetic with the post caval and its 

 tributaries seems to be closer than in the female, a fact which may 

 possibly be correlated with the greater development of the vasa 

 efferentia in the former sex. Proceeding posteriorly from this point 

 the longitudinal strand becomes thicker and the ganglia rather 

 larger, particularly in the male. At about the twelfth or thirteenth 

 ganglion the strand divides very definitely into two, and, while they 

 may be connected by fine strands, they do not re-unite to form a 

 single strand until the posterior end of the kidney is reached. The 

 more dorsal of these strands (sym.d.) remains associated with the 

 dorsal aorta. It receives the rami communicantes and is ganglionated. 

 It is always connected with the ventral strand by a pair of strong com- 

 missures, one lying anterior and the other posterior to the iliac 

 artery. Connexions may also exist in other regions, but they are 

 variable. The ventral strand (sym.v.) remains ventral to the aorta 

 but dorsal to the post-caval vein, and thus continues the direct line of 

 the anterior portion of the strand. It is also ganglionated and remains 

 in close connexion with the adrenal bodies. At the posterior end of 

 the kidney, around the bases of the superficial renal arteries, the two 

 sides of these ventral strands anastomose freely, and form a plexus. 

 The pair of extra large ganglia situated in this region virtually ter- 

 minate the ventral strands, since a fine nerve leaves each ganglion 

 and passes dorsalwards around the posterior margin of each kidney 

 and joins the dorsal strand, which then enters the haemal canal and 

 continues as the caudal portion. The pair of ganglia just mentioned 

 apparently represent the large median cloacal ganglion described by 

 Heidenhain (i 890) for Triton, and although they remain paired and 



