THE LYMPHATIC SYSTEM. 251 



receives twig-s from the M. peroneus, the M. tibialis posticus, the M. 

 gastrocnemius, and a large cutaneous branch. 



a. The Vena cutanea cruris medialis (Fig". 165 i') receives branches 

 from both above and below, and enters the popliteal space to join 

 the anterior tibial vein. 



/3, The anastomosis on the dorsum of the foot, from which the 

 anterior tibial vein arises, receives perforating" twigs from the 

 plantar surface. 



PART IL 

 THE LYMPHATIC SYSTEM. 



(The arrangement of this section has been considerably altered.) 



[The lymphatic system of the frog may, for descriptive purposes, 

 be advantageously treated of in four parts : 



1. The subcutaneous lymph-sacs. 



2. The lymph -hearts. 



3. The lymph-spaces of the body, and those lying between 

 the varioTis organs. 



4. The lymph-vessels of the separate organs. 



The first two parts will be described in this section ; the remainder 

 with the organs or parts of the body with which they are more 

 intimately associated. The spleen will be described with the ab- 

 dominal viscera. 



1. The Subcutaneous Lymph-Sacs. 



A number of large spaces exist between the skin and the muscles, 

 in which there is no direct attachment between these parts. These 

 spaces are separated from each other by thin connective-tissue 

 septa, stretched between the muscles and the skin, and by attach- 

 ments of the skin to the underlying structures. 



Joh. Millier first demonstrated that these spaces were connected 

 with the lymphatic system, and that the contained fluid was lymph. 

 Although this fact was contradicted by Meyer it received confirma- 

 tion from Stannius, Leydig, and especially from Recklinghausen, 

 who showed that the fluid of the lymph-sacs was carried away by 

 the lymphatics, and that later it entered the blood-stream. 



