PARASITISM IN RELATION TO BIRDS. 51 



of a gizzard. This hampers it in flight by the extra weight in 

 front, and has even altered the shape of its breast-bone. 



In the stomach of the Great Crested Grebe, which lives on 

 fish, we never find stones or pebbles, but only feathers ; why so 

 no one has hitherto explained. 



Tradition has it that the Snipe and Woodcock live by 

 " suction," consequently they are cooked without the removal of 

 the entrails. 



These facts show what a vital relation exists between the 

 food (therefore the method of feeding) and the structure of the 

 bird. 



In the same way a vital connection no doubt exists between 

 the food and the parasite infesting the bird. Quoting Eobert 

 Newstead's records from the supplement to the ' Journal of the 

 Board of Agriculture ' of Dec. 9th, 1908, on the " Food of British 

 Birds," it is seen that from his observations the insects chiefly 

 found in the stomach contents, putting them in order of fre- 

 quency, are : — 



(1) Weevils (Rhynchophora) . 



(2) Dung Beetles (Scarabceidce). 



(3) Two- winged flies and their larva (Leather Jackets). 

 Then comes a scale of others which we will neglect. He 



ultimately comes to the conclusion that birds on the whole are 

 beneficial to the interests of horticulture and agriculture. Each 

 species of birds, he states, has its own particular diet. 



These observations by so able an authority confirm the fact 

 that the probability of finding the solution to the occurrence of 

 particular parasites in particular species of birds lies in the parti- 

 cular diet characteristic of that species. 



Further Observations. 

 Occurrence of Extra Cceca in Birds Examined. — An exami- 

 nation of the table shows the presence of extra cseca in birds 

 examined. The cseca, in most cases, were granular in com- 

 position, and the lumen was very small. They varied from 

 j-inch to f -inch in length, and generally occurred about nine 

 inches above the ordinary cseca. Most of the Mudlarks* showed 

 extra caeca. 



* Local name for Rock-Pipit (Anthus obscurus). 



