384 SYMPATHETIC NERVOUS SYSTEM. 



Bibliography of the Peripheral Nervous System. 



(351) F. M. Balfour. "On the development of the spinal nerves in Elasmobranch 

 Fishes." Philosophical Transactions, Vol. clxvi. 1876; vide sdso, A monograph on the 

 development of Elasmobranch Fishes. London, 1878, pp. 191 — 216. 



(352) W. His. "Ueb. d. Anfange d. peripherischen Nervensystems. " Archiv f. 

 Anat. u. Physiol., 1879. 



(353) -A- M. Marshall. "On the early stages of development of the nerves in 

 Birds." Journal of Anat. and Phys., Yo\. XI. 1877. 



(354) A.- M. Marshall. "The development of the cranial nerves in the Chick." 

 QtMrt. J. of Micr. Science, Vol. xviii. 1878. 



(355) A. M. Marshall. "The morphology of the vertebrate olfactory organ." 

 Quart. J. of Micr. Science, Vol, xix. 1879. 



(356) A. M, Marshall. "On the head-cavities and associated nerves in Elasmo- 

 branchs." Quart. J. of Micr. Science, Vol. xxi. 1881. 



(357) C. Schwalbe. " Das Ganglion oculomotorii." Jenaisclie Zeitschrift, Yol. 

 XIII. 1879. 



Sympathetic nervous system. 



The discovery that the spinal and cranial nerves together with 

 their ganglia were formed from the epiblast was shortly afterwards 

 extended to the sympathetic nervous system, which has now been 

 shewn to arise in connection with the spinal and cranial nerves. The 

 earliest observations on this subject were those contained in my 

 Monograph on Elasmobranch Fishes (p. 173), while Schenk and 

 Birdsell (No. 361) have since arrived at the same result for Aves 

 and Mammalia. 



In my account of the development of these ganglia, it is stated that 

 they were first met with as small masses situated at the ends of 

 short branches of the spinal nerves (fig. 275 sy.g). More recent inves- 

 tigations have shewn me that the sympathetic ganglia are at first 

 simply swellings on the main branches of the spinal nerves some way 



below the ganglia. Their situation may be 

 understood from fig. 274 sy.g, which belongs 

 however to a somewhat later stage. Subse- 

 quently the sympathetic ganglia become re- 

 moved from the main stem of their respective 

 nerves, remaining however connected with 

 those stems by a short branch (fig. 275 sy.g). 

 I have been unable to find a longitudinal 

 commissure connecting them in their early 

 '^y; 7 stages ; and I presume that they are at tirst 



„ . -. ' independent, and become subsequently united 



VERTICAL SECTION THROUGH i^to a coutlnuous cord on each side. 

 PART OF THE BODY WALL OF Thc observatlous of Schenk and Birdsell 



AN Elasmobranch embryo ^^ ^Yie Mammalia seem to indicate that the 



SHEWING PART OF TWO SPINAL . , p , i ,^,• x 



NERVES AND THE SYMPATHETIC main parts ot the sympathetic system arise 



GANGLIA BELONGING TO THEM, in contiuuity with tho posterior spinal gan- 



ar. anterior root; jpr.pos- gHa; they al SO shew that in the neck and 



^:iZ-Z!'p^ST^t- other parts the sympathetic cords arise as a 



cle-plate. continuous ganglionic chain. The observa- 



