Fig. 203.—Alimentary canal of Galeus canis, dog-shark, in
section, showing spiral intestinal valve. (Columbia University
Museum, No. 1429.)
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 cæca 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 Pleuronectidæ have three to five.
Fig. 205.—Alimentary canal of Polypterus
bichir. (Columbia University Museum, No.
1823.)
Fig. 206.—Alimentary tract of Echelus conger, Conger eel. Stomach, mid- and end-gut,
liver, and spleen. (Columbia University Museum, No. 1430.)
Fig. 207.—Stomach, duodenum, and pyloric cæca of Lophius piscatorius, angler.(Columbia University Museum, No. 1824.)
Fig. 208.—Pleuronectes maculatus, window-pane. Stomach and mid-gut withpyloric cæca and hepatic duct. (Columbia University Museum, No. 1432.)
Fig. 210.—Paralichthys dentatus, summer flounder. Stomachand mid-gut with pyloric cæca and liver. (Columbia UniversityMuseum, No. 1431.)
Fig. 209.—Pleuronectes maculatus, window-pane. Stomach and mid-gut withpyloric cæca, in section. (Columbia University Museum, No. 1433.)
Fig. 211.—Pyloric cæca of Gadus callarias, codfish. (Columbia University Museum, No. 1825.) A. Bound together by connective tissue and blood-vessels.
B. Dissected to show confluence of cæca to form a smaller number of terminal tubes of larger calibre entering the intestine.
