The anatomy of Lottia gigantea Gray. 



25 



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 ofl". Now rising 

 slightly , the artery 



makes a complete Fig. I. Dorsal view of visceral mass showing the 



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



curve, just in iront OI spreads over the upper layers of the liver and over the 



the proximal end of stomach. AiU.Ao anterior aorta, S stomach, X portion of 



, , , J. vein-net of right kidney (R. K) to show manner of formation 



ine Stomacn ana lore- ^^^^^ ^^le branches of visceral artery. 



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 



