THE VOYAGE OF THE * CHALLENGER.' 385 



In Ossifraya gigantea (fig. 9) the tongue is very elongated, three 

 inches long, and narrow proportionally. Its apex is slightly emarginate, 

 and there is a deep groove for about two fifths of its length, and 

 traceable further back to the base of the tongue. The base has a fringe 

 of pointed spines, which are continued, of smaller size, along the lateral 

 margin for some way, there being some very much smaller spines 

 developed inside them on the borders of the tongue for about an inch, 

 though not reaching the posterior angles of the organ by half that 

 extent. 



In Pelecandides (fig. 2) the tongue is fleshy, and fairly parallel-sided, ^ ' Tol & iy ' 

 tapering apically. It is but little free, and occupies most of the inter- pt. 3d. p. 21. 

 space between the mandibular rami. Its base is notched, and provided 

 with some largish spines, which continue forwards for about the basal 

 half, or more, of the lateral margins. On the dorsal surface there is 

 always a peculiar lanceolate mark, apparently due to a difference in the 

 nature of the mucous membrane covering the tongue over this area. 



The oesophagus which in the Albatrosses, as already described by 

 Pavesi, may be surrounded at its commencement with a zone of spines, 

 continuous below with the spines covering the laryngeal eminence is 

 always capacious and distensile, but possesses no crop. Inferiorly, in 

 the thorax, it passes without any marked constriction or other difference 

 into an enormous proventriculus, which is a thin- walled bag, reaching 

 down nearly to the posterior extremity of the abdominal cavity, which it 

 largely occupies, lying to the left side of the stomach proper and the 

 mass of the intestines. This great proveutricular bag is twisted back on 

 itself apically, and then, becoming' slightly narrower, passes by a small 

 aperture into the stomach proper or gizzard. This aperture is therefore 

 to the right of, and anterior to, the great " f undus,'" which lies freely in 

 the posterior part of the abdominal cavity, covering there the terminal 

 portion of the intestine and cloaca. Internally, the proventricular 

 glands are seen to cover pretty uniformly the whole surface of the 

 mucous membrane, with the exception of a more or less narrow zone 

 which lies between this glandular part and the stomach proper, corre- 

 sponding pretty nearly to the narrower, ascending part of the bag as seen 

 from outside (vide PI. XIY. fig. 1 and PL XV. fig. 15). The extent of 

 this very deep " zonarv " proventriculus (pr.) is always very considerable 

 in the Petrels, being of course, cwteris paribus, larger in the larger than 

 in the smaller species. In Majaqueus its ex'ent is 4*0 indies; in Pele- 

 canoides, 1/85 inches ; in Fregetta grallaria, 1*2 inches. 



The stomach proper (</.) is always small and more or less globular, 

 with fairly muscular walls and provided with the usual central tendinous 

 sheets, so that it may fairly be called a gizzard. Its situation is peculiar, 

 lying always above and to the right of the proventricular fuudus, and 

 with its pyloric part so flexed on itself that it looks backwards instead 



2c 



