72 ALLEN 



gall-bladder artery (PI. IV, fig. 34; A.G.Bl.A.). In case 

 such a branch is given off it usually supplies the above men- 

 tioned gland (see fig. 34; G.) The third branch of the right 

 gastric is the air-bladder retia mirabilia or anterior air-bladder 

 artery (PI. IV, fig. 31 ; A.Bl. A.) ; it crosses above intestinal 

 arterY(,j and the right anterior spermatic vessels, just in front of 

 the right mesenteric and the anterior air-bladder veins. Pene- 

 trating the thick ventral muscular walls of the air-bladder it 

 breaks up internally into small branches, which in turn break 

 up into minute parallel arterial capillaries, that become contin- 

 uous distad with parallel venous capillaries, and which are 

 afterward collected into small veins that empty into the air- 

 bladder retia mirabilia vein. This sort of a horseshoe-shaped 

 mass of capillaries on the floor of the air-bladder is known as 

 the retia mirabilia or vaso-ganglion of the air-bladder ; it is a 

 vaso-ganglion of the bipolar type. This broad expanse of 

 capillaries affords a good opportunit}' for the exchange of gases 

 from the blood to the bladder and conversely. The fourth and 

 last branch to be given off from the right gastric artery is the 

 left anterior sfe^-matic artery (PI. IV, fig. 31 ; L.Sper.A.). 

 This vessel pursues a similar course to the right anterior sper- 

 matic artery, following parallel with the corresponding vein it 

 helps supply the left ovary or testis and anastomoses poste- 

 riorly with the spermatic arter}^ proper. /;;/c5//7/rt'/rt'r/'dr;'j(j) (PI. 

 IV, fig. 31 ; Int. A.,) pursues a general caudal course, passing 

 under or rather to the right of all the above mentioned arteries. 

 When in the neighborhood of the spleen it divides ; the pos- 

 terior fork, which is designated as the continuation of the main 

 intestinal artery^j), passes caudad to supply the posterior end of 

 the intestine ; while the anterior fork soon divides into the 

 splenic artery and what I have designated as intestinal artery^g). 

 Intestinal artery ^..^ (PI. IV, fig. 31 ; Int. A. 2) is so named be- 

 cause it runs parallel with a vein, which has the same terminus 

 as intestinal vein ^2^ of Ofhiodon^ but it is hardl}^ probable that 

 this artery is homologous with intestinal artery(2) of Ophiodon. 

 This artery separates into an anterior branch, which supplies 

 the anterior part of the intestine or duodenum and a posterior 

 branch, which supplies the iliac part of the intestine. In some 



