Yosef Karo, Shulchan Aruch — 47: The law if there are extra intestines
“ Contains five Seif.1 A beast that has two intestines is treif, for instance when it has two intestinal tracts from the beginning to end, next to each other from beginning to end like the intestines of a bird. Or if the intestines branch off from the material - but now behold there's a difference between the case of a bird and a beast - but if it goes back and joins again with the intestines and becomes one formed from the two lines but they're just clearly separate in the middle - behold it's permitted and there is no Yeter (extra) here. ”
