STUDIES ON AVIAN H^MOPROTOZOA. 683 



21, (B) d, (c) 9; fig. 73-(a) 25, (b) 2^, (c) 10 ; fig. 7— (a) 25, 



(b) 2^, (c) 29 ; fig. 75— (a) 26, (b) 3i (opposite nucleus) ; (c) 

 11; and again, fig. 79— (a) 21, (b) 2^, (c) 15; fig. 77— (a) 

 23, (b) 3, (c) 19 ; fig. 88— (a) 26, (b) 3^ (opposite nucleus), 



(c) 14. The measurements are given in a slightly different 

 manner from that adopted in the case of the parasites when 

 in the bird. In the cultural forms the length of the body- 

 by itself affords a better means of comparing the size of 

 different individuals than the length of the body plus that 

 of the flagellum. This is because of the great and 

 apparently indiscriminate variation in the length of the 

 flagellum, which cannot be said to bear any relation to that 

 of the leugth of the body. This is well seen by contrasting 

 figs. 80 and 81, from a redpoll culture, with figs. 84 and 83, 

 respectively, from achafiinch culture. This diversity is chiefly 

 due to the manner of division, as will be explained shortly. 



Smaller forms, very similar in appearance to some of the 

 larger ones indicated, are seen in figs. 85 and 86; the 

 former is 17 by If/i and its flagellum 7hfji. The smallest 

 parasites observed, however, belong to, or result from, a 

 slightly modified variety of the above type. This is somewhat 

 different in appearance (figs. 8, 97), but it really represents 

 only another facies, as it were, of the same trypanomonad 

 type, from which it is derived by the gradual drawing back 

 of the nuclei well into the aflagellar half of the body, and by 

 a somewhat modified manner of division which is then 

 found (concurrently). 



As the process of multiplication plays an important part in 

 tlie development of these various forms, it may be as well to 

 give a general morphological description of it here before 

 proceeding farther. The mode of division by which the 

 long, slender trypanomonad forms are produced is that of 

 equal or subequal fission of the body. Sometimes the two 

 daughter-flagella are practically equal (figs. 11,96), but in 

 the majority of cases one of the flagella is distinctly longer 

 than the other (figs. 91-95). In all the instances I have 

 noticed, the division of the cytoplasm begins at the flagellar 



