THE INTESTINAL PROTOZOA OF FROGS AND TOADS. 257 
large intestine or in the discharged excrement of frogs, have 
a very characteristic appearance (see Pl. 5, figs. 81, 82). 
They are active and show a well-marked ectoplasm and endo- 
plasm (fig. 81). The protoplasm itself often shows a most 
striking alveolar structure, which is no less marked in the 
living animal than in a fixed and stained specimen (compare 
figs. 81 and 82). In the living state also the structure of the 
nucleus is seen quite as distinctly as in a stained preparation. 
It is characterised by a large central mass of chromatin, 
separated by a clear zone from the membrane. Its structure 
corresponds very well with that figured in “ Leydenia” by 
Schaudinn. It is impossible to mistake this amoeba for 
Entamceba ranarum (compare figs. 81 and 52). A con- 
tractile vacuole is sometimes, but not always, to be seen. 
When present it can often be seen to arise as several small 
vesicles, which fuse together during the diastole. 
Although the amcebe are sometimes to be found in large 
numbers I have never succeeded in finding dividing forms. 
According to Schaudinn they are capable of multiplying both 
by equal bipartition and by budding. 
It is interesting to note that they will live and apparently 
multiply—though I have never found dividing individuals—in 
saline albumen solution. On one occasion when I transferred 
some amcebe into a culture dish containing the albumen 
solution, I found that after the lapse of twenty-four hours 
they had increased considerably in numbers and were very 
active. Owing to drying of the solution many of the amcebee 
subsequently encysted. ‘This ability to live thus is of interest 
in connection with Schandinn’s statement that “ Leydenia” 
is really the Chlamydophrys ameba. 
After creeping about in the feces for some time the 
amoebee come to rest and develop into the typical adult form. 
They do this by rounding themselves off and developing a 
shell—a thin, shining, white, porcellaneous structure. It is 
oval in shape, with the opening at the apex (see fig. 80, 
Pl. 5). Through the opening, the animal protrudes delicate 
filose pseudopodia, which serve to catch its food. 
