[Illustration: FIG. 200.--Abdominal viscera of dog, showing arrangement of pancreatic ducts. (Nuhn.)] [Illustration: FIG. 201.--Section of dog's stomach, and proximal portion of duodenum, with entrance of biliary and pancreatic ducts. (Columbia University Museum, No. 1822.)] The parts in _Hyaena_ present a similar arrangement. Bernard always found _two_ pancreatic ducts in the _cat_, one large principal duct and a second smaller accessory duct. Of these, the one situated nearest to the pylorus always united with the bile-duct. The pancreatic duct thus joining the bile-duct was sometimes the main duct, sometimes the accessory smaller duct. Since the main function of the pancreatic juice is the conversion of starch into sugar, the gland appears better developed in general in herbivora than in carnivora, without, however, disappearing in the latter. In fact it is of considerable size in the carnivora, because the secretion also acts on the albuminous food substances and, though to a lesser degree, on the fats. PYLORIC CAECA OR APPENDICES. In the _Cyclostomata_ and _Selachians_ the intestinal canal is in the main free from caecal appendages, while a large portion of the tube is provided with a special fold of the mucous membrane which projects into the lumen of the gut (spiral valve). Fig. 43 shows the straight intestinal tract with the spiral valve of the longer distal segment in a cyclostome, _Petromyzon marinus_ or lamprey. In Figs. 202 and 203 the selachian (shark) intestine is represented in two examples, while the similar spiral valve in a Dipnoean or lung fish, _Ceratodus_, is seen in Fig. 204. [Illustration: FIG. 202.--Alimentary tract with spleen and pancreas of _Squalus acanthias_, the dog-fish. (Columbia University Museum, No. 1405.)] [Illustration: FIG. 203.--Alimentary canal of _Galeus canis_, dog-shark, in section, showing spiral intestinal valve. (Columbia University Museum, No. 1429.)] [Illustration: FIG. 204.--Alimentary canal with spiral valve of _Ceratodus forsteri_, the Australian lung-fish (Barramunda). (Columbia University Museum, No. 1645.)] On the other hand in the Ganoids and in many Teleosts longer or shorter finger-shaped diverticula of the midgut are found immediately beyond the pylorus in the region of the bile-duct. These pouches or diverticula of the intestine form the so-called pyloric caeca or appendices of these fish. They vary very much in length, diameter and number in different forms. Thus but a single diverticulum appears in _Polypterus_ and _Ammodytes_ (Fig. 205). _Rhombus maximus_ and _Echelus conger_ (Figs. 112 and 206) have two, and the same number appear in _Lophius piscatorius_ (Fig. 207). Perca has three and the _Pleuronectidae_ have three to five. [Illustration: FIG. 205.--Alimentary canal of _Polypterus bichir_. (Columbia University Museum, No. 1823.)]