THE INTESTINAL PROTOZOA UF FROGS AND TOADS. 207 
batrachorum Perty. There are, however, in reality two, 
a Trichomonas and a Trichomastix. I will begin with 
the latter. 
(a) Trichomastix batrachorum Dobell. 
I have already described this organism in my preliminary 
note (12). It differs structurally but little from other species, 
and is very common. It may occur alone, but is more 
commonly found in company with Trichomonas. 
Structure.—Inallessential points this animal’s structure 
is identical with that of Trichomastix serpentis, which I 
have elsewhere described (56). 
The general external form is usually ovate or pyriform, but 
subject to a certain amount of modification (see PI. 2, figs. 
1-3). The nucleus lies at the anterior end of the body, and 
is ovoid and composed of chromatin granules of irregular 
size and shape. A nuclear membrane is usually seen. Lying 
in front of the nucleus and generally in close apposition is a 
minute granule which stains with chromatin stains very 
intensely. This granule is often seen to be really double 
(cf. figs. 1, 3), and it serves as the point of origin of the four 
flagella. For reasons which will be apparent later I shall 
call this little diplosomic structure the blepharoplast.' 
Of the flagella, three are directed forwards whilst the 
fourth is turned backwards (cf. fig. 3, etc.). 
The flagella are not the only organelle which find an 
attachment to the blepharoplast. A flexible rod-like organ 
is also firmly fixed to it, and runs backwards to end in the 
caudal process of the animal. This organ is one of the most 
characteristic features of the trichomonads, and although it 
has often been observed in Trichomonas, its significance 
has not always been properly understood. Its real function 
is undoubtedly skeletal. It serves as a fixed point for the 
anchorage of the flagella. Since the structure is one which 
1 The name was first used for trichomonads by Laveran and Mesnil 
(65). 
