III. 
AVIAN FILARIAE. 
— New Species 
This description of new blood filariae discovered in West African birds of 
different species includes the account of eight new species, of which the adult forms 
generally both male and female were found, as well as the blood embryos, and 
also of three species in which blood embryos alone were met with. 
With a view to obtaining some uniformity in the descriptions and measure- 
ments of Nematode worms in general, Cobb 1 has devised an ingenious formula, for 
the account of which we are indebted to Shipley 2 , in which measurements of different 
parts appear as percentages of the whole length of the body. The following diagram 
explains the nature of the formula, which, however, should be used with caution since 
it rests on the assumption, as Shipley 1 points out, that the proportions of the various 
parts of the body are constant in different individuals, and it is by no means certain 
that this is the case. 
In the diagram, 6, 7, 8, 10, and 6 are the transverse measurements, while 7, 
14, 28, 50, and 88 are the corresponding longitudinal measurements. The formula 
in this case is 
7 14 28 50 88 
~~ 6 7 8 10 6 ' 
The unit of measurement is the one-hundredth part of the length of the worm, so 
that the measurements are therefore percentages of the length. The measurements 
are taken with the animal viewed in profile ; the first is taken at the base of the 
oesophagus, the second at the nerve ring, the third at the cardiac constriction, the 
fourth at the vulva in the female and at the middle in the male, the fifth at the anus. 
1. Cobb, Macleay Memorial Volume, Sidney, 1893, p. 252 ; and Pioc. Linnean Society, N.S.W. 
Second series, Vol. V, 1890, p. 449. 
2. Shipley, Harmer and Shipley, Cambridge Natural History, Vol, II, Worms, etc., p. 138. 
