THE DEVELOPMENT OF LYMPH CHANNELS IN TURTLES BY 

 THE FUSION OF MESENCHYMAL SPACES. 



BY FEANK A. STROMSTEN. 



1. The theory that the lymphatic system is budded off from the ven- 

 ous system is a direct product of a special method of investigation, i. e., 

 the injection method. 



2. The injection method alone is entirely unreliable, because: (a) 

 Only that portion of the lymphatic system which is in direct connection 

 with the point of injection (lymph sacs) is shown, the unconnected 

 spaces are not indicated, (b) Extravasations and venous injections 

 vitiate the results. 



3. Serial sections, both injected and uninjected, of turtle embryos 

 of different ages show the successive stages of the development of 

 lymphatics from the spongy mesenchyme surrounding the aorta and 

 larger arteries, through the formation of independent spaces which 

 constantly enlarge and finally fuse to form continuous channels. 



4. The endothelium of the lymphatics arises entirely independent 

 of the venous endothelium from the original mesenchymal cells. 



