FORE-GUT OF CORYDALIS CORNUTUS L. 583 



The main trunk passing forward first gives off another small 

 branch which also goes to the caecum. Then it divides into 

 two branches. The anterior one, breaking up into three small 

 branches, supplies the caudal portion of the gizzard. The pos- 

 terior branch divides into three branches which send numerous 

 small tracheae to the caudal part of the gizzard, the esophageal 

 valve and the ventral caecum. 



The third tracheal trunk (fig. 1, d) arises at the base of the 

 transverse dorsal trachea of the third abdominal segment. It 

 proceeds forward and divides into two branches, one of which, pass- 

 ing in between the caeca, supplies them with numerous branches 

 and also send tracheae to the fore-gut between the gizzard 

 and mid-gut. The other branch passes to the dorsal side of the 

 dorsal caecum and furnishes it with a tracheal supply. It also 

 sends numerous small branches to the anterior portion of the mid- 

 gut and the region of the fore-gut behind the gizzard. 



The fourth tracheal trunk (fig. 1, e) arises in a way similar to 

 the second — from the base of the fourth tracheal gill. It passes 

 forwards and divides into two branches. The posterior one sup- 

 plies the ventral and lateral surfaces of the mid-gut. The 

 anterior one divides into many small branches which supply the 

 anterior and lateral portions of the mid-gut as well as the proxi- 

 mal ends of the caeca and caudal part of the fore-gut. 



The fifth tracheal trunk (fig. 1, g) arises similarly to the third. 

 Directly at the point of origin or very near it, there is given off 

 a large branch (in some cases two) which goes to the testis. This 

 branching frequently varies on the opposite sides of the same indi- 

 vidual. The main branch proceeds forwards and divides just 

 before reaching the digestive tract. The two branches supply 

 the anterior dorsal and lateral portions of the mid-gut as well as 

 the proximal ends of the dorsal caeca and posterior end of the 

 fore-gut. 



A sixth trunk (fig. 1, /) arises from the fifth tracheal gill. It 

 divides into two branches which supply the posterior end of the 

 mid-gut. 



From the photograph (fig. 1) and the above description it will 

 be seen that the gizzard and mid-gut are well supplied with a 



