( 94) 



the intercostal arteries, is described by Gaskeli. ^) from tiie second 

 thoracic unto the second lumbar nerve in man. I did not observe 

 a similar splicing in the Monotremes. 



The most caudal branch of the sympathetic chord to tlie abdominal 

 viscera leaves this chord in Ornithorhynchus at the level of the 

 entrance of the ramus visceralis of the eighteenth thoraco-lumbar 

 nerve, in Echidna at that of the nineteenth thoraco-lumbar nerve. 



So the caudal limit of the visceral nerves in Monotremes is much 

 lower than in man, in whom this limit is described by Bishop 

 Harman ^), in accordance with Gaskell at the level of the fifteenth 

 thoraco-1 umbar nerve. 



In the caudal part of the sympathetic chord I found branches of 

 it united with the pudendic nerve. In Ornithorhynchus these connect- 

 ing branches arose froui the chord at the level of the sacral and 

 lii-st caudal nerve, in Echidna at the level of the first till third 

 caudal nerves. The plexus hyi)Ogastricus, which in mammals is found 

 on the side of the caudal rectum end and the uro-genital canal, 

 I found only slightly developed in Monotremes. 



A few observations about the ramiiications of the sympathetic 

 branches to the abdominal viscera may be added here. 



On the medial side of the suprarenal body two groups of nerve 

 fibres appear (in the figures each of them is represented by one 

 single line). 



The topmost of the two groups is going to the origin of the Arteria 

 coeliaca -|- mesenterica superior (Fig. 1 and 2 a. c. m.) and passes 

 into the plexus coeliacus, in which in Ornithorhynchus two separate 

 ganglia are to be distinguished. The plexus coeliacus also receives 

 a branch of the Nervus vagus. 



The second group of nerve fibres runs to a little quadrangular 

 ganglion, situated in the peritoneum at the medial side of the kidney, 

 which I will call ganglion renale (Fig. 1 and 2 g.r.). The ganglion 

 renale sends off small nerve fibres to the kidney, to the plexus 

 coeliacus (or in opposite direction) and continues at its caudal end 

 into a nervestem, which runs parallel with the aorta. 



In Ornithorhynchus this nervestem ends in a ganglion (Fig. 2 g.g.j 

 which also receives the already described caudal limiting branch for 

 the abdominal viscera. 



1) W. Gaskell. The sympathetic nervous system. Nature 1895. 



2) N. Bishop Harman. The caudal limit of the lumbar visceral efferent nerves 

 ill man. 



Journal of Anat. and Physiol. Vol. 32 pg. 403. 



