252 



THE VASCULAR SYSTEM. 



A. The Lymph-sacs of the Head and Trunk. 



a. The septa. The connective-tissue septa themselves contain 

 sinuses which occupy the space between their two surfaces (Fig- 

 1 66): these septal sinuses receive the contents of the cutaneous 

 lymph-vessels and forward their contents into lymph- vessels situated 

 in the septa. Such a sinus is shown in transverse section in Fig-. 

 1 66, which is a section of the ventral septum. The same sinus, in 

 plan, is seen in Fig". 167. 



(i) The dorsal septum [Sepônm dorsale), (Fig-s. 169 and 171 d) of 

 each side commences at the tympanic membrane ; it is then attached 

 to the M. depressor maxillae, 31. infraspinatus, and M. longissimns 



Fig. 167. 



Transverse section of a seji- 

 tiim with the attached 

 skin, its contained sinus 

 injected with Wue injec- 

 tion mass. 



// Skin. 

 .V Seiitum . 



.S Sinus contained in the 

 septum. 



The sinus ahdominalis lateralis (Ecker) injected 

 with blue mass. 



U Skin with its lymph- vessels. 



S Sinus of the septum with lymph-vessels 



opening into it. 

 s The septum cut parallel with the skin. 



dor si; and continued backwards over the M. obliqnus abdominis 

 externvs to the anterior end of the M. ghdaeus, whence it extends 

 along the iliac bone, where it is connected with the posterior 

 lymph-heart and the M. pyriformis, to the tip of the urostyle. At 

 the tip of the M. glutaeus it is joined by the iliac septum. The 

 posterior part of the septum is horizontal, and forms the roof of the 

 iliac lymph-sac. 



(2) The ventral sei^tura {Septum abdominale), (Figs. 169, 170, and 

 171 a), commencing at the Symphysis p^ubis, runs forwards and out- 

 wards, on either side, along the outer border of the M. rectus abdom- 

 inis to the Portio abdominalis of the M. ptectoralis {p"'), where it is 

 attached, at a right angle, to the pectoral septum ; it then extends 

 forwards, after attachment to the axillary septum, to the outer 



