470 DEVELOPMENT OF ELASMOBRANCH FISHES. 



The siiprarenal bodies. 



My observations on these bodies in the adult Scyllium have 

 only been made with specimens hardened in chromic acid, and 

 there are many points which deserve a fuller investigation than 

 I have been able to give them. 



The general position and relations of the suprarenal bodies 

 have been fully given by Leydig and Semper, and I have nothing 

 to add to their statements. They are situated on branches of 

 the aorta, segmentally arranged, and extend on each side of the 

 vertebral column from close behind the heart to the posterior 

 part of the body-cavity. The anterior pair are the largest, and 

 are formed apparently from the fusion of two bodies 1 . When 

 these bodies are examined microscopically, their connection with 

 the sympathetic ganglia becomes at once obvious. Bound up 

 in the same sheath as the anterior one is an especially large 

 ganglion already alluded to by Leydig, and sympathetic ganglia 

 are more or less distinctly developed in connection with all the 

 others. There is however considerable irregularity in the develop- 

 ment and general arrangement of the sympathetic ganglia, which 

 are broken up into a number of small ganglionic swellings, on 

 some of which an occasional extra suprarenal body is at times 

 developed. As a rule it may be stated that there is a much 

 smaller ganglionic development in connection with the posterior 

 suprarenal bodies than with the anterior. 



The different suprarenal bodies exhibit variations in structure 

 mainly dependent on the ganglion cells and nerves in them, 

 and their typical structure is best exhibited in a posterior one, 

 in which there is a comparatively small development of nervous 

 elements. 



A portion of a section through one of these is represented on 

 PL 19, fig. 6, and presents the following features. Externally 

 there is present a fibrous capsule, which sends in the septa, im- 

 perfectly dividing up the body into a series of alveoli or lobes. 

 Penetrating and following the septa there is a rich capillary 

 network. The parenchyma of the body itself exhibits a well- 



1 There is a very good figure of them in Semper's paper, PI. xxi. fig. 3. 



