Pyloric appendices, 119 function of, 221 in _Accipenser_, 120 in _Gadus_, 120 in _Lophius_, 120 in _Paralichthys_, 120 in _Pelamys_, 120 in _Perca_, 120 in _Pleuronectes_, 120 in _Rhombus_, 120 in _Scomber_, 120 in _Thynnus_, 120 relation to pancreas, 121 significance of, 120 appendix in _Ammodytes_, 120 in _Echelus_, 120 in _Polypterus_, 120 caeca, 119 function of, 221 stomach, 50 valve, 44 in fishes, 45 of loon, 45 _Rana_, alimentary canal of, 55 _catesbiana_, ileo-colic junction of, 201 _esculenta_, venous system of, 158 Ratitae, ileo-colic junction and caeca of, 203 Rectal gland of Selachians, 201 Rectangular ileo-colic junction, 225 Recto-coccygeal muscles, 33 Recto-uterine muscles, 33 Rectum, development of, 54 separation from genito-urinary sinus, 27 Renal-portal circulation in Urodele Amphibian, 156 system in Selachian, 154 in _Iguana_, 159 Reptilia, abdominal vein, 167 biliary ducts in, 145 ileo-colic junction of, 201 Retro-gastric peritoneal space, boundaries of, 175 space, rudimentary form of, 105 Retro-peritoneal hernia, 92 Reticulum, 49 _Rhombus_, pyloric appendices in, 120 Rodentia, caecal pouch of, 229 compound stomach of, 49 ileo-colic junction of, 211 spiral colic valve of, 231 Rodents, saccus lymphaticus of, 196 Round ligament of liver, 152 Rumen, 49 Ruminantia, structure of stomach in, 49 Saccus lymphaticus of _Lepus cuniculus_, 211 of Rodents, 196 _Salamandra maculosa_, venous system of, 158 Salivary glands, derivation of, 34 Saurians, stomach of, 44, 46 Sciatic vein in _Iguana_, 160 _Scincus ocellatus_, stomach of, 45 _Scomber_, pyloric appendices in, 120 Segmental veins in _Iguana_, 160 Segmentation, 20 Segmentation-cavity, 20 Selachian, caudal vein in, 154 digitiform gland of, 201 duct of Cuvier, 155 hepatic portal system of, 155 lateral vein of, 155 pancreas in, 116 rectal gland of, 201 renal portal system of, 154 spiral intestinal valve in, 119 venous system, 154 _Semnopithecus_, stomach of, 47 Septum urogenitale, 27 transversum, 142 Serous folds in cases of Meckel's diverticulum, 262, 263 membrane, derivation of, 31 Shape of caecum and origin of appendix, 245 of embryonic caecum, 245 Sheep, biliary ducts in, 145 development of pancreas, 115 Sigmoid flexure, development of, 54, 77 _Simia satyrus_, ileo-colic junction and caecum of, 216 Sinus venosus, 146 Sirenia, ileo-colic junction of, 208 Soft palate, 42 Somatic mesoderm, 21 Somatopleure, 22, 29 Spigelian lobe, boundaries of, 170 development of, 169 recess of lesser sac, 177