Internal iliac artery, 63 perineal folds, 27 Intestinal blood vessels, effect of intestinal rotation on, 59 canal of _Amphioxus_, 191 of Amphibians, 191 of Cyclostomata, 191 diverticula, 193 of Dipnoeans, 191 of Teleosts, 191 folds of mucosa, 193 non-differentiated, of lower vertebrates, 191 folds in Amphibia, 196 in birds, 195 in fish, 196 furrow, primitive, 22 glandular apparatus in lower vertebrates, 195 groove, primitive, 22 juice, function of, 194 mucous membrane of _Cervicapra_, 196 of _Echelus conger_, 197 _Lophius_, 197 lymphoid tissue, 196 of _Phocaena_, 196 of _Thalassochelys_, 197 rotation, 58 arrest of development, 60 demonstration in cat, 67 spiral fold, function of, 193 vascular supply, 63 in cases of non-rotation, 67 villi of Carnivora, 195 of _Casuarius_, 195 of Ophidia, 195 of _Ursus maritimus_, 195 Intestine in early human embryo, 52 general consideration of, 51 large, and caeca of _Hyrax_, 234 functions of, 198 length of, 199 of monkeys, 199 of rodents, 199 width of, 199 small, 192 absorbing apparatus, 195 divisions of, 194 length of, 192 secretory apparatus, 194 structure of, 194 villi, 195 Isthmus, duodeno-colic, 57 Jejuno-ileum, development of, 54 _Labrus_, stomach of, 44 _Lagomys pusillus_, colon and caecum of, 232 _Lagothrix humboldtii_, ileo-colic junction and caecum of, 215 Lamellirostra, ileo-colic junction and caeca of, 203 Lateral vein in Selachian, 155 _Lemur macaco_, ileo-colic junction and caecum of, 213 _mongoz_, ileo-colic junction and caecum of, 213 Lemuroidea, ileo-colic junction of, 213 _Lepus cuniculus_, ileo-colic junction and caecum of, 211 saccus lymphaticus of, 211 Lesser curvature, first appearance of, 41 Ligament, colico-lienale, 109 of ductus venosus, 152 gastro-lienale, 110 lieno-renale, 109 phrenico-lienale, 109 Ligamenta coli, 199 Liver in Chelonians, 144 comparative anatomy of, 144 derivation of, 34 development of, 141 function of, 195 lobation of, 144 in Ophidia, 144 peritoneal lines of reflection in embryo, 167 in foetus at term, 171 peritoneal relations of, 167 of _Petromyzon_, 141 unilobar type, 144 _Lophius_, biliary ducts in, 145 _piscatorius_, mucosa of midgut, 197 pyloric appendices in, 120 stomach of, 46 Lungs, derivation of, 34 _Lutra_, biliary ducts in, 145 stomach of, 48 Lymphoid tissue of intestinal mucosa, 196