AMG@BA PROTEUS. Al 
separated, and their posterior position may be tem- 
porarily lost. According to Penard the elliptic, discoid, 
punctated nucleus is characteristic of this species. 
In the larger examples of Amaba proteus the pos- 
terior ectoplasm habitually contracts, and, in doing so, 
forms a mass of “short digitate or mulberry-like 
processes.” These, however, are not permanent. They 
appear to be modified or latent pseudopodia, which 
are, so to speak, grouped together and dragged behind 
by the animal in its progress. In some, and those 
always the largest individuals, they are conspicuous. 
Leidy’s observations showed that they eventually get 
absorbed in the general mass, or, in response to some 
change in the creature’s motion, develop into active 
pseudopodia and are used as such. 
The endoplasm of A. proteus is usually charged with 
a considerable variety of extraneous material. Inter- 
mixed with chlorophyl-pellets there may be seen re- 
fringent bodies resembling oil-globules, and granules 
-of starch. The former are probably adventitious sub- 
stances, of no significance physiologically, though 
Leidy was of opinion that they might prove to be an 
intrinsic element. The starch-grains may have been 
incepted with the food. There are, in addition to 
these, minute crystals of quartz or calcium carbonate, 
or both, in variable quantity. 
Although the food of A. proteus consists for the most 
part of chlorophyl-bearing alge, such as diatoms and 
desmids, the animal, like others of its class, preys occa- 
sionally on other Protozoa, and even on the Rotifera. 
Plate I, fig. 3, and Pl. ITI, f. 2, represent a remark- 
able variety, distinguished by its mulberry-shaped 
caudal extremity and finely-granular endoplasm. In 
the latter there is no admixture of oil-like globules or 
other adventitious matter, but green corpuscles are 
present, which in all the examples met with were of 
uniform size and very numerous. ‘The nucleus and 
contractile vesicle are normally as in A. proteus, but in 
general aspect and mobility this form is so distinct as 
