SEA-FISHERIES LABORATORY. 801 



crosses it at right-angles. In front of this is found the 

 seventh spinal sympathetic ganglion (7 7 ). At this region 

 the two cords are connected by a transverse commissure 

 below the dorsal aorta and bearing a pair of ganglia (7"), 

 formed as shown in the figure, and the cord of the right 

 side is also looped. There are two B/R. communicantes to 

 the ventral ramus of the sixth spinal nerve (com. vi.), but 

 in front of this, beyond a loop for a renal vein and a very 

 small ganglion in front of ganglion 5 (o') } there are no 

 features of special interest until we come to the second 

 spinal sympathetic ganglion. 



The sympathetic behind the second ganglion lies 

 immediately above the inner dorsal angle of the kidney. 

 The coeliac ganglion (g. coel.) lies close under the second 

 spinal sympathetic (2'j, and in front rises up to fuse with 

 it. Four nerves arise from the second ganglion. Behind, 

 a pair (com. ii.) pass independently into the ventral ramus 

 of the second spinal nerve, and thus form RR. communi- 

 cantes ii. The sympathetic now lies internal to the 

 kidney, and just above the cceliaco-mesenteric artery. 

 In front, a large third nerve arises dorsally, and soon splits 

 into an anterior and a posterior branch. The former is 

 continued into the first ganglion (V) and thereafter into 

 the cranial sympathetic, whilst the latter forms a promi- 

 nent ganglionated (2") commissure under the dorsal aorta 

 with the cord of the other side. The fourth branch arises 

 anterior to the third, and curved backwards on to the 

 aorta, where it was lost. The second ganglion now tapers 

 down, and terminates in close proximity to the kidney. 



The coeliac ganglion, which it should be noted arises 

 from the right sympathetic cord, passes backwards after 

 fusing with the second ganglion, and is situated just over 

 the coeliaco-mesenteric artery. It also gives off four 

 branches, The most dorsal one passes straight into the 



