THE INTESTINAL PROTOZOA OF FROGS AND TOADS. 243 
parasitic flagellate forms with four equal anterior flagella. I 
think it best to retain this genus, therefore, for the parasitic 
quadriflagellates—reserving Tetramitus for free forms. 
The general structure of the animals is shown in figs. 49 
and 50, Pl. 3. Two different forms are here seen—a small, 
slender Crithidia-lke form (fig. 49) and a larger and 
broader one (fig. 50). The size of the small forms is about 
10-12 x 2p. The larger forms reach dimensions up to 
20m xX 7m. All intermediate sizes occur. 
One of the features which most markedly distinguish this 
organism from those already described is the presence of a 
very well-marked cuticle. This is best seen, perhaps, in 
Giemsa preparations, where it stains pink, in contrast with 
the blue cytoplasm. 
The four flagella are equal in length, and are all directed 
anteriorly : that is to say, there is no “ Schleppgeissel” as in 
Trichomastix. 
The nucleus is a large, oval body, composed of loosely- 
packed chromatin granules. It is placed anteriorly. The 
origin of the flagella is immediately in front of the nucleus. 
Sometimes they appear to arise directly from it (fig. 49), 
whereas at other times they seem attached to a small granule 
lying above and independent of the nucleus (fig. 50). Several 
vacuoles are usually seen in Giemsa preparations, but these 
are not visible in the hving animal. There is no cytosome or 
axostyle. 
When alive the organism progresses by characteristic jerky 
movements, rather like a Bodo. ‘They are exceedingly active 
when first removed from their host. 
Owing to the paucity of material I have not been able to 
ascertain anything of the hfe-history. In cultures of the 
toad’s feces all the animals died without showing any signs 
of encysting. From the fact that I have several times observed 
—in stained preparations—animals with eight flagella, it 
appears probable that they divide longitudinally in the usual 
flagellate manner. But the nuclear division and subsequent 
stages I have not been able to find. 
