viii JoiTRNAi. OF Comparative Neurology. 



The column can be traced as far as the level of the mouth and caudad 

 as far as the Wolffian bodies, where it becomes connected with a mass 

 of mesoderm cells which form one portion of the supra-renal bodies. 

 This rod is mesodermal in origin; it is formed i)i situ, and it is unseg- 

 mented and unc: nnected with the spinal nerves. 



In rat embryos at about ten days cellular outgrowths from the cellu- 

 lar sympathetic cord can be traced ventrally round the aorta, especially 

 in the region of the kidney, and in front of it to form the collateral 

 ganglia, and to join the supra-renal bodies. 



The superior (dorsal) primary division of the spinal nerve is not yet 

 differentiated into separate roots. The somatic part of the inferior, 

 (ventral) primary division has divided into its dorsal and ventral 

 branches. The sphlanchnic part is directed inwards above the card- 

 inal vein and reaches nearly to the sympathetic cord. 



In mouse sections at eleven days the union between the sphlanchnic 

 branch and the sympathetic is complete. 



In front of the fore limbs and behind the kidney no such connection 

 of the sphlanchnic branch with the sympathetic can be made out. 



Up to the time of the formation of the vertebral centra there is no 

 gangliation or constriction of the main sympathetic cord. 



The formation of ganglia is determined first, by the entrance of the 

 sphlanchnic nerves; second, by the position of the cord with reference to 

 the vertebral column. 



The sphlanchnic branches correspond to the white rami coiinnmii- 

 cantes and are derived from both the dorsal and ventral roots of 

 the spinal cord. 



The gray i-anti communicantes arise from the sympathetic cord as 

 cellular outgrowths, which find their way along the sphlanchnic branches 

 to their central connections. 



The Epiphysis and the Parietal Eye.(') 



This discussion of the relation of the epiphysis to the so-called 

 parietal eye is timely and fills an important gap in our knowledge. 

 While anything like a complete construction of the facts presented 

 must await embryological investigation of these types, yet the observa- 

 tions are suggestive. 



Mr. Ritter describes the parietal vesicle in Phyrosoma as lying 

 within the parietal foramen, though extending somewhat above the 

 parietal bone and firmly imbedded in connective tissue. The various 

 tissues above the parietal vesicle are all modified and the skin is unpig- 

 mented. A cord of connective tissue passes from the end of the 

 epiphysis to the sheath of the vesicle, but no evidence could be secured 

 of their actual passage through the walls. The wall of the vesicle 



I \V. E. RriTkK. The Parietal Eye in some Lizards from the Western United 

 States. Bulletin of the Museum of Coiiiparniive Zoology,}nn., 1891. 



