34 NILS HJ. 0DHNER, STUDIES ON RECENT CHAMIDAE. 



011 the left and on the right side, some of the latter being the lowest and opening 

 just in the upper part of the duodenum. 



Beneath the large anterior liver duct the stomach grows narrower and passes 

 into the duodenum. In transversa] (horizontal) section it appears to have an elliptical 

 outline and an oblique position to the sagittal line. Its foremost portion is separated 

 from the larger posterior part by a septal band, thus forming a narrow groove. As 

 the duodenum descends, the septum grows broader and the furrow thus becomes deeper, 

 while on the other hand the larger cavity of the duodenum becomes narrower. Be- 

 sides this the duodenum is somewhat twisted, so that the smaller furrow is, in- 

 feriorly, placed on the right. At their lower end both parts of the duodenum pass 

 into the intestine, only the left one forming a small pouch beneath the transition 

 point. The intestine describes a turn backwards and a second one forwards and 

 then runs with a weak S-formed curvation and without any dilatation towards the 

 pericard, which it penetrates, as well as the heart, continuing its course in the usual 

 manner on the posterior side of the adductor to the anal orifice. 



The stomach as well as the duodenum are kept stable by strong muscular 

 cords radiating from their walls to the muscular layer of the body surface (fig. 30). 



The liver forms a bipartite mäss, the left lobe of which lies more to the front 

 and the right one is extended more backwards and more upwards. Both terminate 

 at about the level of the genital pores. The anterior liver canal receives ducts from 

 both the left and the right liver folliculi, the branches on the left side debouching 

 at a lower, the ones of the right side at a higher level. 



The circulatory system. The heart has comparatively small auricles, well 

 separated from each other on both sides of the likewise small ventricle. From the 

 latter there emerges, as usua], an anterior aorta on the dorsal side of the intestine and 

 a posterior one on its ventral side. Immediately after its exit from the ventricle, 

 from which it is bounded by a valve, it widens into a large sinus which gives rise 

 to two branches. The dorsal one divides again into two vessels, of which the su- 

 perior one runs forwards above the stomach and ultimately enters the mantle; it 

 gives off a short descending branch on the right of the stomach. The inferior ves- 

 sel passes beyond the left side of the stomach towards the oesophagus, and follows 

 the left side of the latter to the vicinity of the mouth. Here it gives rise to a wide 

 branch directed towards the front and forming a large sinus on the left and back 

 side of the stomach, while the smaller trunk of the vessel passes on, somewhat to 

 the left of the median line, into the foot as arteria pedalis. From the oral sinus 

 one branch penetrates forward on the left side to the adductor and a smaller one 

 emerges to the right of the oesophagus likewise to the adductor. 



The ventral branch of the anterior aorta is arteria gastrica. It descends im- 

 mediately from the sinus in an oblique direction out of the left side of the stomach. 

 Close beneath the posterior coecal sac of the stomach the arteria gastrica bifurcates 

 to the two sides of the stomach. Each of its branches then descends perpendicu- 

 larly, the left one at the frontal part of the duodenum, the right one along its 

 median line. 



