CIRCULATORY ORGANS. 



305 



There is also a large lymph sinus in the scapular region into which the trunks from 

 head and body empty. Frequently there is also a large caudal sinus (physostomes) 

 connected with a lymph heart (fig. 310) which forces the lymph into the caudal 

 vein. 



The urodeles have the thoracic ducts united behind but separate in front, a 

 cephalic trunk emptying into each, and each duct opening into the corresponding 

 subclavian vein, while a series of from fourteen to twenty lymph hearts occur in 

 connexion with the trunk accompanying the lateral line. The anura are noticeable 

 for the complete disappearance of the thoracic ducts, their place being taken by a 



FIG. 311. Deeper anterior lymphatics (stippled) of Scorpenichthys, after Allen, a, 

 auricle; abs, abdominal sinus; b, brachial sinus; br, brain; cs, cephalic sinus; d, dorsal trunk; 

 fm, facialis-mandibularis vein; hs, hyoid sinus; ij, inferior jugular vein; ips, inner pectoral 

 fin sinus; j, jugular vein; /, lateral trunk; on, orbi to-nasal vein; p, pericardial sinus; pf t 

 profundus facialis lateral trunk; pv, profundus ventral trunk; sf, superficial lateral trunk; 

 ssl, superior spinal longitudinal trunk; v, ventricle; va, ventral aorta; vfs, ventral fin sinus; 

 i-p, ventral pericardial sinus; vt, ventral abdominal trunk. 



pair of trunks between the dorsal myotomes and those of the lateral body wall. 

 They have also enormous subcutaneous lymph spaces, separated from each other 

 by narrow partitions. It is the presence of these large spaces that makes the skin- 

 ning of a frog such an easy matter. Two pairs of lymph hearts are present, one 

 pair in the neighborhood of the extremity of the urostyle, the other between the 

 transverse processes of the third and fourth vertebrae. In the caecilians there is a 

 pair of lymph hearts for each segment of the trunk. 



Reptiles have two cephalic lymph trunks and one (lizards) or two thoracic 



