WILSON'S PETREL. 



227 



along the edge of lower mandible y^; tarsus If; middle toe 1, its claw T ^. 

 Weight l-§- oz. 



Adult Female. 



The female resembles the male. 



The palate is marked behind with four longitudinal ridges, which are 

 papillate, and before with three ridges; the mouth A\ twelfths in width, but 

 capable of being dilated to 9 twelfths; the 

 tongue \ inch long, triangular and acuminate, 

 at the base concave and emarginate, fiat above, 

 with a slight median groove. The lobes of 

 the liver are equal, their length 7^- twelfths. 

 The oesophagus, a b, has a uniform width of 

 3 twelfths until it enters the thorax, when it 

 at once expands into an immense ovate sac, 

 b c de, 1 inch 11 twelfths long, viewed ante- 

 riorly 1 inch 1 twelfth in breadth, laterally 

 1 inch 2 twelfths. This sac is formed, pro- 

 perly speaking, of the proventriculus; its 

 walls are extremely thin and transparent, 

 and it is studded all over with roundish 

 glandules placed at a considerable distance A 

 from each other. It curves upwards in front, 

 and becomes narrowed to 2 twelfths, ending 

 in the stomach, which is an extremely di- 

 minutive gizzard, of an oval form, only 3j 

 twelfths long, and 3 twelfths in breadth. The 

 stomach is thus reversed in position, its 

 fundus being anterior; and accordingly the intestine,/^ h i, comes off from 

 its left instead of its right side, forms a semicircular sweep round the fundus, 

 then passes backward for 1 inch, to f, bends forward to the liver, at g, and 

 forms a number of loops, g h i, making in all 9 turns. The duodenum is 1 

 inch | twelfth wide, and the intestine continues so for half its length, when 

 it gradually contracts to f twelfth, and is rather less in the rectum, which is 

 terminated by a very small globular cloaca, j, 3^ twelfths in diameter. 

 There are no cceca. The intestine measures 14 inches. The stomach pro- 

 perly so called is lined by a rugous epithelium, and is in fact a true gizzard. 

 It contains a quantity of shell-sand. The inner surface of the proventriculus 

 is soft and smooth; that of the oesophagus longitudinally plicate. The trachea 

 is 1^- inches long, from \\ twelfths to 1 twelfth in breadth, flattened, with 

 rings 84 in number, slender, and unossified. Bronchi wide, of 25 half rings. 



