PARASITISM IN RELATION TO BIRDS. 



47 



which are very highly specialized in relation to the environment 

 of very intensified gastric secretion. 



N.B. — The number of endo-parasites seems to increase with 

 the increase of ecto-parasites, which lends itself to the assump- 

 tion that the lice may serve as intermediate hosts in most species 

 of birds. 



It is a well known fact that the greater number of lice are 

 found on the head region, and especially near the mouth, which 

 fact makes it conceivable that the parasite can easily find access 

 into the alimentary canal of the final host (bird) from this 

 possible intermediate host (lice), of which as yet so few have 

 been discovered to the hosts. 



The parasites found were Cestodes and Nematodes, and on 

 examining the number of birds investigated, and the number of 

 these parasites found, the proportion of Cestodes to Nematodes 

 proved to be 4'4 Cestodes for every one Nematode ; showing that 

 4*4 times more Cestodes were found than Nematodes. On the 

 other hand, connecting the number with the numbers of birds 

 infested, it was found that : — 



Thirty-two per cent, birds infested by Cestodes. 

 Twenty-five per cent, birds infested by Nematodes. 



The following is a table with a classification of parasites 

 found in the different birds : — 



Parasite. 



Starling. 



Thrush. 



Blackbird. 



L. M. Gull. 



Curlew. 



Dilepis undula 



Cheanotania parina 

 (?) 



* 



* 









Monopylidium mus- 

 culosum 





Anomatcenia con- 

 stricta 





A. nymphc&a 



* 







Family Hymenolepidid;e (Eaillet & Henry). 

 Family Diagnosis. 



T^ENIOIDEA. 



(1) Scolex with an armed rostellum or without. 



(2) Hooks on rostellum, not hammer-shaped. 



