The anatomy of Lottia gigantea Gray. 



25 



QuvK- 



The visceral artery supplies the alimentary canal, and liver. It is 

 one of the largest vessels in the animal, being exceeded in carrying 

 capacity only by the anterior aorta, and possibly by the genital artery. 

 The vessel begins by a funnel-like prolongation of the buccal sinus 

 backward into the visceral mass. Here the vessel soon divides 

 (Fig. 21), the divisions being the two limbs of a complete loop as 

 shown in the figure. 

 Within the visceral ar- 

 tery is the radula tube 

 which thus curves 

 around and reenters 

 the buccal sinus to 

 become attached to the 

 anterior aorta by the 

 end of the sheath. 

 Starting with the left 

 limb, which is the chief 

 blood channel, we will 

 find that the artery 

 dips slightly downward 

 into the lower layers 

 of the liver, under all 

 the alimentary tract, 

 then curves to the left 

 and lies next to the 

 oesophagus to which 

 numerous branches are 

 given off. Now rising 

 slightly , the artery 

 makes a complete 

 curve, just in front of 

 the proximal end of 

 the stomach and fore- 

 chamber. To the left 

 of the proventriculus a very large branch is given off to the hind 

 portion of the viscera. This immediately divides into a dorsal and 

 a ventral part. The former (Figs. 1 and 21 Dors. Br) passes directly 

 upward and divides sometimes into three, but usually into two 

 (anterior and posterior) branches. The smaller branches redivide 

 excessively and form a fine network through the upper layers of the 



Fig. I. Dorsal view of visceral mass showing the 

 dorsal branch of visceral artery (Fig. 21 Dors. Br) which 

 spreads over the upper layers of the liver and over the 

 stomach. Ant. Ao anterior aorta, 8 stomach, X portion of 

 vein-net of right kidney (i?. K) to show manner of formation 

 from the branches of visceral artery. 



