STEGANOPODES 



416 



VEAY in Audubon's ornithological miscellany, it has been more fully 

 described and illustrated by Gabeod and Poebes. One great 

 peculiarity is that in P. anhinga the proventricular glands, instead 

 of forming a patch, or patches, upon the inner surface of the 

 proventriculus, constitute a special csecal diverticulum of the 

 stomach, which is completely lined by the glands in question. 

 The pyloric portion of the stomach forms a well-marked compart- 

 ment, quite distinct from the gizzard region ; the opening of the 

 pylorus into the duodenum is protected by a dense mat of hair- 

 like processes, each of which is about half an inch in length. 

 Microscopically these structures ' are much more like true hairs ' 

 than hke any filiform papillae which might occur in such places. 

 In P. Levaillanti there is no special compartment for the pyloric 

 proventricular glands. The hairs lining the pyloric chamber have 

 a more complex arrangement than in P. anhinga. There is 

 (fig. 193) a dense mass of them lining the distal end of the pouch, 

 but there is also a singular conical process of the mucous mem- 

 brane, covered with more hairs and serving to close the pylorus. 

 P. melanogaster agrees with the last species, but the plug is less 

 developed, being rather a well-defined ridge than a retractile plug. 

 Mr. PoEBES thinks, that this hairy plug of the darters is an 

 exaggeration of the nipple-like valve which is found to guard the 

 pylorus in many birds. The two Old- World species thus come 

 nearer together, as they do in the ossification of Donitz's bridge, 

 than does either to the New- World P. anhinga. 



In order to facilitate a comparison of the several genera 

 of Steganopodes among themselves, the annexed table, indi- 

 cating the differences in some of the muscles, viscera, and 

 bones, may be of use : — 



The Steganopodes, though allovs^ed by all to be a natural 



