V. R. RAJAGOPALAN AND M.
ISRAIL
43
These observations, therefore, show
at:
(1) Both in Labeo rohita and Cir-
rhina mrigala:
(i) when the pectoral fin is less
than or equal to the anal the
specimen is always a female;
but a female may also have
pectoral fins greater than the
anals;
(ii) when the pectoral fins are
greater than the anal, the
specimen may be a male or a
female, but in the male the
pectoral fins are always greater
than the anals;
(2) In Labeo rohita in the females,
the pectoral fins though they
may be greater than the anals,
are
always less developed
than the pectorals of the males
for the same length of fish. The
same rule, with a few exceptions,
applies to Cirrhina mrigala too.
Thus, given the same lengths of fish, it
is easy to distinguish male and female
in both these species, but in other cases it
is rather difficult to do so, except in the
breeding season when the females have
bulging bellies due to the presence of ova
in the ovaries and can easily be re-
cognised.
The results obtained by Mookerjee [1938
1 and 2] are, therefore, not of universal
application and it would be interesting to
know if the two species of carp namely
Labeo rohita and Cirrhina mrigala show
similar variations with regard to the
pectoral and anal fins in other parts of
India as those observed in the Punjab.
REFERENCES
Cunningham, J. T. (1900). Sexual Dimorphism in
animal Kingdom..
Adam and Charles Black.
London 185-86.
Mookerjee, H. K. (1938,1) Report of the Scheme for the
Investigation of the Life History, Bionomics and
Development of Fresh Water Fishes in Bengal, for
the period from 1st December, 1936 to 31st October,
1937. Government of India Press, Simla. 6.
——
(1938,2) Determination of sex from
the external features of Labeo rohita Gunther and
Cirrhina mrigala Cuv. and Val.' Indian J, vet.
Sci 8,41.
STREPTOCOCCI FROM EQUINE STRANGLES IN INDIA
By V. R. RAJAGOPALAN, G. M. V. C., DIP. BACT. (MANCH.) and M. ISRAIL, G. V. Sc.,
Imperial Veterinary Research Institute, Mukteswar
(Received for publication on 14 June 1944)
THE demand for the preparation of a
strangles vaccine for experimental use in
the field led us to examine streptococci
from cases of strangles with a view to
solate virulent strains of Streptococcus
equi. It was remarkable that contrary to
expectation out of eleven strains of strep-
tococci isolated from strangles abscesses,
only one conformed to the description of
Str. equi.
Schutz [1887] discovered the strepto-
coccus of strangles but Sand and Jensen
[1888] gave an adequate description, and
designated the organism, Str. equi This,
however, was often confused with other
closely-related streptococci from equines.
Evans [1936] has referred to the common
but erroneous practice of calling any
streptococcus recovered from a disease in
horses diagnosed as strangles, 'Strepto-
coccus equi'. This was especially the
case when streptococci were classified by
Holman's method. When Ogura [1929]
and more particularly Edwards [1933]
showed the value of trehalose and sorbitol
as additional reagents, substrains could
be more clearly distinguished. The studies
of Bazely and Battle [1940] on haemolytic
streptococci from equine infections have
thrown fresh light on the subject. Besides