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Show 1896.] ANATOMY O F P E T R O G A L E X A N T H O P U S . 713 marked on the posterior part of the dorsum. Foliate papillae are present in their normal position but are feebly marked. There are three circumvallate papillae, the central one being well marked, while the lateral ones are indistinct and situated just in front of the papillae foliatae. The Tonsils answer to Owen's description x; each consists of eight or ten nodules of lymphatic tissue about the size of a pin's head lying in a well-marked fossa just beneath the soft palate. The Parotid Gland, as is usual in the Macropodidae, is very large and reaches from the root of the ear along the side of the neck, dorsal to the external jugular vein, almost to the scapula. The Submaxillary Gland is small and oval, and is situated on the ventral side of the external jugular vein just clear of the angle of the jaw. The Sublingual Gland is very small. The (Esophagus is long and narrow and has a considerable course in the abdom. i. The Stomach of Petrogale penlcillata has been carefully examined bv Beddard and contrasted with that of Bendrolagus bennettii2. The stomach of Petrogale xanthopus agrees with his description and I shall content myself with mentioning that it measured 24 inches along the greater curvature and 13 along the lesser. The Spleen differs from that of Bendrolagus and resembles the normal marsupial arrangement in being distinctly A-shaped ; the stalk and posterior limb of the A together measure 5| inches, the anterior limb 2 inches. The stalk and posterior limb evidently correspond to the spleen of other mammals, because the gastro-splenic omentum is attached along them. Apart from the place where the extra limb comes off there are no notches in the spleen. The Liver of Petrogale penlcillata has been figured by Beddard : the arrangement of its lobes agrees very accurately with that of P. xanthopus; the same notch is present in the Spigelian lobe, though it is less well marked. The Pancreas is about 6 inches long, its head is surrounded by the duodenum, while the long thin tail reaches the spleen. The Small Intestine is 8 ft. 6 in. long, the Large, 3 ft. 8 in.; this is about the same proportion that Beddard describes in Bendrolagus. Garrod3 says that in Borcopsls luctuosa the large intestine is one-third the length of the small; in Petrogale, however, the proportion is greater. The bile-duct opens into the duodenum 3 inches from the pylorus, the pancreatic duct just beyond. In the Great Kangaroo, O w e n says that the bile and pancreatic ducts unite and open 5 inches from the pylorus. The Caecum is 6 inches long, and is not sacculated as O w en describes it in the Great Kangaroo; its calibre is greater than that of the rest of the colon; the ileum joins it at an acute angle, and 1 ' Anatomy of Vertebrates,' vol. iii. p. 385. 2 P. Z. S. 1895, p. 131. 3 P. Z. S. 1875, p. 56. PEOC. ZOOL. SOC.-1896, No. ^LVI, 46 |
