386 OJS T THE PETRELS COLLECTED DUEING 



of forwards as in all ordinary birds (vide PL XIV. fig. 1 and PL XV. 

 fig. 15), in this respect somewhat resembling the stomach of Struthio. 

 In Struthio, however, the pyloric aperture is on the deep (dorsal) side of 

 the stomach, nearly in the middle line, and so concealed when the viscera 

 are viewed from the abdominal aspect. In the Tutinares the pyloric 

 aperture, on the other hand, is quite superficial, lying at the inferior 

 (posterior) end of the gizzard in the angle formed by the two parts of 

 the bent proveutriculus. 



The gizzard, which is nearly always found full of the horny beaks of 

 Cephalopoda, is lined internally by an " epithelium/' which is usually 

 dark in colour, and frequently of almost corneous texture, with a more 

 or less corrugated or wrinkled free surface (vide PL XV. fig. 16, where 

 Zool. Chall. the epithelial lining of the everted gizzard of Fulmarus ylacialis is 

 pt X1 xi V01 22 represented *). In the Oceanitidse and Diomedeinae this epithelium, is 

 softer ; its character in other Petrels is but an exaggeration or reproduc- 

 tion of that existing in some other birds, particularly that occurring in 

 such Storks as Xenorhynchus. 



The displacement of the pyloric orifice of the gizzard to the left 

 necessitates a corresponding change in the commencing duodenum, so 

 that this at first ascends in an upward curve towards the right before it 

 returns to form the backwardly-directed loop, characteristic of Aves and 

 Mammalia, round the pancreas (PL XIV. fig. !,.>) 



This peculiar upward curve of the commencing duodenum, the 

 singularly small inverted stomach, and enormously deep proventriculus 

 are all peculiar, so far as I am aware, to the group of Tubinares, though 

 universal amongst them, and no other bird yet examined has, so far as I 

 know, a similar disposition of these viscera f . 



The intestinal caeca are entirely absent in all the Oceanitidse, but are, 

 with one exception, present, though of small size, in the Procellariidse. 

 They are always short and globular, and closely connected to the intes- 

 tine, so as to appear as mere nipple-like projections from it. Plate XIV. 



* The figure of Cams and Otto (Tabulae, Anat. Comp. Illustr. part 4, t. vi. figs. 15, 

 16) of the epithelium of the gizzard of Fulmarus glacialis does not at all faithfully 

 represent what I have seen in two (quite fresh) specimens of that bird, nor have I ever 

 in other Petrels seen epithelium of such a corneous and paveinent-like nature as that 

 figured by them. I have, therefore, had one of my specimens carefully drawn of the 

 natural size. In this place it will be well to recall the still more highly developed 

 gastric epithelium of some of the Fruit-Pigeons (Phcenorhina goliath and Carpophaga 

 latrans) described by Verreaux and Des Murs, Viallanea and Garrod (vide Report on the 

 Birds collected during the Voyage of H.M.S. Challenger, in the years 1873-76, Zool. 

 Chall. Exp. pt. viii. pp. 152-154). 



t The description of these parts in the Little Auk (Alca alle) given by Professor 

 Owen (Anat. Vert. vol. ii. p. 163), and originally due to Home (Lect. Comp. Anatomy, 

 i. pp. 283, 284, 1814), does not all apply to that bird (cf. the figure and description 

 given by Macgillivray in Audubon's ' Ornithological Biography,' iv. pp. 306-309), and 

 probably refers to Borne member of the Tubinares. 



