206 LAGOPUS CINEREUS. 



part, and gradually become thinner ; but this appearance arises 

 from the deposition of the chyle upon the inner surface. 



By means of the short, strong, sharp-edged bill, the bird 

 breaks off small portions of the fresh twigs of Erica cinerea, 

 Calluna vulgaris, Vaccinium Myrtillus, willows and other 

 shrubs, with which and occasionally spikes of Eriophora, 

 carices and junci, berries and other vegetable substances, it 

 gradually fills its crop, which is capable of containing a mass 

 upwards of three inches in diameter. These twigs are all cut to 

 the length of from one to five twelfths of an inch, arrive in the 

 crop slightly moistened, and there appear to undergo no ma- 

 ceration, it being merely a recipient. A quantity passes into 

 the gizzard, a powerful muscular apparatus, in which are 

 lodged numerous fragments of quartz, that is a mineral sub- 

 stance harder than glass, with wdiich it is mixed ; and being 

 compressed by the action of the lateral muscles, is pounded 

 into a kind of dryish pulp, the herbaceous tissue being com- 

 minuted, and the woody fibres broken and torn. In this pulpy 

 state, the mass passes into the upper lobe of the stomach, and 

 enters the duodenum by the pylorus, which rejects the mineral 

 particles. It is then diluted, and has a yellowish-green colour. 

 Beyond the entrance of the biliary ducts, it becomes of a green- 

 ish-brown tint, and tow-ards the coeca is more dry. The chyle 

 adheres copiously to the walls of the upper part of the intestine. 

 The contents of the coeca are a uniform pultaceous mass of a 

 dull yellowish-brown colour, in w^hich vegetable fibres can 

 scarcely be distinguished by the naked eye. In the rectum, 

 on the contrary, the fibres are easily perceived, some of them 

 being from one to two twelfths of an inch long. It would thus 

 appear that the coarser parts pass directly along from the intes- 

 tine into the rectum, and that the more comminuted only enter 

 the coeca. The foeces in the rectum are comparatively dry, 

 and form a continuous cylinder, in wdiich state, mixed w^ith 

 the urine they are voided, forming a small heap of cylindrical 

 fragments, having a dull greenish-yellow colour, mixed with 

 white. 



The Grey Ptarmigan, then, is a bird which, feeding on vege- 

 table substances containing comparatively little nourishment, 



