392 



Avian Filariae 



Filarial embryos are very common in the 

 blood of birds, and the adult forms are found 

 in the most diverse positions, notably in the sub- 

 cutaneous tissues. In some form the embryos 

 appear to be confined to the lymph. 



In the description of Avian -filariae the 

 following should be noted : — 



1. The species of bird concerned. 



2. The site of the adult filariae. 



3. The description of the adult filariae, 

 female and male ; the use of Cobb's formula 

 gives uniformity to descriptions. The measure- 

 ments are taken with the animal in profile from 

 the anterior end. 



(i) To the base of the oesophagus, 

 (ii) To the nerve ring. 

 (iii) To the cardiac constriction. 

 (iv) To the vulva in the female, or to the 



middle in male. 

 (v) To the anus, noting when this is ter- 

 minal. 



At each of these points transverse measure- 

 ments are taken and noted below the above, so : — 



Longitudinal. 

 Transverse. 



The unit of measurement is one-hundreth 

 part of the length of the worm. 



This formula should be used with caution, 

 since it rests on the assumption that the pro- 

 portions of the various parts of the body are 

 constant in different individuals (Shipley). 



