{ 334 ) 



NOTE OX THE EJECTION OF THE LINING- 

 MEMBRANE OF THE GIZZARD BY THE CURLEW. 



BY 



H. HAMMOND SMITH. 



In the Field of March 1st, 1913, a letter from Mr. Dugald 

 Macintyre was pubHshcd in which he said that Curlews 

 periodically eject the lining-membrane of the gizzard 

 " still retaining the grit used in digestion," and in proof 

 of this he forwarded samples of these lining-membranes 

 of the gizzard. These were examined by Mr. R. H. Burne, 

 of the Royal College of Surgeons, who states that they 

 are the lining-membrane of the gizzard, and I am in- 

 debted to him for referring me to notes of the Proceedings 

 of the Zoological Society in which it is shoMn that the 

 Wrinkled Hornbill [Buceros corntgatus), when in the 

 Zoological Gardens, was observed to eject the lining- 

 membrane of its gizzard. 



In Newton and Gadow's Dictionary of Birds, the 

 gizzard or stomach is described as varying greatly, in 

 different species of birds, in size, shape, strength, and 

 position — chiefly according to the kind of food eaten. 

 On the whole, the walls of the gizzard retain the same 

 laj^ers as the rest of the alimentary canal, but the muscular 

 layer is more strongly developed, while the tunica mucosa 

 or lining-membrane contains mucous glands alone, and 

 none producing any specific or chemically-acting secretion. 

 Two kinds of gizzard, the simple and the compound, 

 may be conveniently distinguished, though they are con- 

 nected by intermediate stages. In the simple gizzard 

 the tunica tnucosa contains simple glands secreting a soft 

 cuticular lining, which is constantly renewed and easily 

 peels off as a viscous yellow coating ; the compound 

 gizzard is lined with a thick brownish cuticle, formed by 

 the hardened secretion of the tunica mucosa, consisting 

 of numerous lamella which are continuously reproduced 

 by the secret ing-cells to supply those that are Avorn down 

 by the constant trituration of the food through the action 

 of the lateral muscles. 



