110 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ III, I
Length of oral sucker about 1/15 body length; diameter of posterior
sucker about 1/5 body length.................................... P. macaci.
Length of oral sucker about 1/7 body length, diameter of posterior sucker
10/25 body length................................................... P. hawkesi.
The points of difference raised above for distinguishing the three species are
more apparent than real, based as they are on the observation of a limited number
of specimens and the conclusions drawn from them are necessarily fallacious.
With a view to test the validity of the inferences drawn by Fukui data on the
lines suggested by him were obtained from 14 specimens, the result of which is
tabulated below :—
1 |
2 |
3 |
4 |
5 |
6 |
7 |
|
Total length of body |
5.7 |
5.2 |
6.2 |
5.3 |
5.3 |
4.7 |
5.9 |
Length of oral sucker/ Total length |
0.42/5.7=1/14 |
0.33/5.2=1/16 |
0.52/6.2=1/12 |
0.52/5.3=1/10 |
0.68/5.3=1/8 |
0.43/4.7=1/11 |
0.34/5.9=1/17 |
Diameter of postorior sucker/ Total length |
1.33/5.7= ¼ |
1.25/5.2=¼ |
1.38/6.2=1/5 |
1.32/5.3=¼ |
1.14/5.3=1/5 |
0.97/4.7=1/5 |
1.22/5.9=1/5 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
|
Total length of body |
6.3 |
6.4 |
6 |
6.7 |
6 |
6.6 |
5.8 |
Length of oral sucker/ Total length |
0.54/6.3=1/12 |
0.52/6.4=1/12 |
0.53/6=1/11 |
0.47/6.7=1/14 |
0.58/6=1/10 |
0.52/6.6=1/13 |
0.55/5.8=1/11 |
Diameter of posterior sucker/ Total length |
1.02/6.3=1/6 |
1.42/6.4=1/5 |
1.24/6=1/5 |
1.52/6.7=¼ |
1.53/6.6=1/5 |
1.24/6.6=1/5 |
1.2/5.8=1/5 |
It will be seen from the above that the ratio of the length of the oral sucker
to the total length of the body varies considerably, i.e., from 1/8 to 117 and that
the one between the diameter of the posterior sucker to the total length also varies,
although within a smaller range. The ratio in the latter case worked out by Fukui
in P. hawkesi is 2/5, which again is far from that existing in the above 14 specimens.
It is therefore suggested that the various ratios worked out by Fukui are not of