chap, xi.] THE LYMPHATIC VESSELS. 91 



and fourth vertebra; it is slightly smaller than the 

 posterior one. The lymph hearts have an efferent ves- 

 sel, which is a vein, and from them the venous system 



Fig. 56. Developing Lymph-oapillaries in tne Tail of Tadpole, 

 a, Solid nucleated protoplasmic branches not yet hollowed out. (Atlas.) 



of the neighbourhood can be easily injected, whereas 

 the reverse is not possible. They are lined with an 

 endothelium like the lymph sacs, and in their 

 wall they possess plexuses of striped, branched, 

 muscular fibres. The nerve fibres terminate in these 

 striped muscular fibres in the same manner as in those 

 of other localities. (Ranvier.) 



