142 



DIGESTIVE SYSTEM 



descending branch lies, when viewed from the ventral side, to the 

 right of the second or ascending branch ; both invariably enclose 

 the Pancreas. 



A loop which runs in the same Avay- as the duodenum may be 

 termed rifjld-handed, and one running in the opposite way is left- 

 handed, i.e. its descending branch lies to the left of the ascending- 

 branch. Again, if the intestine forms a number of (mostly closed) 

 loops, which run parallel with each other in the long axis of the 

 bod}'', we term this arrangement orthoaelous, or straight-gutted. 



J 



d 



h 



DlAIIRAMMATIO RePRKSENTATION OF THE PRINCIPAL RELATIVE POSITIONS OF THE INTESTINAL 



Loops when sees from the right side. 

 ■a. Isoctflous. T}. Anticoelous. c. Anti-Periccelous. d. Iso-Pericoelous. 



e. Cyclocwlous. /, </. Plagiocoelous. h. Telogyrous. 



The descending branches of tlie loups are marked by black lines, the ascending or return- 

 ing branches ai'e dotted. 



The tirst and third loops in fig. h are " right-handed," the second is "left-handed " ; iu tig. c 

 tlie second is "left-," the third "right-handed." etc. 



(From the Proceedings of the Zoological Societij, 18S9.) 



If, on the other hand, some of the loops form a spiral, we dis- 

 tinguish this formation as ci/rlanelous. 



Of the uiilioadons type the following modifications deserve espe- 

 cial remark with reference to the second and third loops ; the first, 

 or duodenal, loop is invariably right-handed, and therefore needs 

 no further comment. 



I. Isorcehmx. — The second and third, and, if present, also the 



fourth loop are all closed and left-handed. The second is most 



■ dorsally situated, the third to the right of it, the fourth to the 



