286 ALBERT KUNTZ 



in all sections, while in some sections they appear on the lateral 

 sides of the sympathetic anlagen and are not apparent on the 

 mesial sides. 



It may be noted at this point that while in the eight-day stage 

 such light areas sometimes appear in contact with the loose cell- 

 aggregates constituting the anlagen of the sympathetic trunks, 

 there is no evidence of such areas of weakness in the mesenchyme 

 along the paths of migration of the cells which wander from the 

 distal ends of the spinal ganglia into the anlagen of the sympa- 

 thetic trunks before the spinal nerves may be traced peripherally. 

 In view of this fact and in view of the fact that the connections of 

 the anlagen of the sympathetic trunks with the spinal nerves along 

 the paths of the communicating rami arise after the anlagen of 

 the sympathetic trunks are already present, it does not seem 

 probable that in embryos of the turtle the anlagen of the sympa- 

 thetic trunks grow peripherally in lymph spaces, but rather that 

 lymph spaces are formed in contact with the sympathetic anlagen. 

 My observations on embryos of Thalassochelys and on embryos 

 of Chelydra are in full agreement on this point. Lymph spaces 

 in contact with the anlagen of the sympathetic trunks cannot 

 be satisfactorily traced in the later stages in embryos of the tur- 

 tle because, as will be shown presently, the anlagen of the sympa- 

 thetic trunks soon become more or less scattered and no longer 

 appear as compact cell-aggregates. 



At the close of the eleventh day of incubation the anlagen of 

 the sympathetic trunks have become somewhat larger and more 

 conspicuous. They now lie in closer proximity with the aorta 

 and are connected with the spinal nerves by comparatively thick 

 fibrous communicating rami (fig. 3, C. R.). The anlagen of the 

 sympathetic trunks no longer appear as definitely limited cell- 

 aggregates, but are becoming somewhat scattered. In trans- 

 verse sections they appear to be made up of several irregular cell- 

 groups more or less closely associated with each other (fig. 3, 

 Sy.). Such scattering of the anlagen of the sympathetic trunks 

 is less apparent in the anterior than in the posterior region of the 

 body. In the anterior region the anlagen of the sympathetic 

 trunks appear in transverse sections as somewhat transversely 



