ARCHER—ON RHIZOPODA. 2al 
some navicular diatom of considerable comparative length, which causes 
the ordinary orbicular form of this Rhizopod to become distorted more 
or less, and to assume an elongate, or elliptic or broadly spindle-shaped 
figure. When an unusually long diatom is taken in, it may cause the 
normal outline of the Rhizopod to project to a comparatively great extent 
beyond the ordinary limits at its two ends, these being then invested by 
an exceedingly thin and tense stratum of the sarcode body, and only a 
single layer of the outer vesicles spread over the whole. In fact, it 
sometimes may look as if the diatom projected right through and 
through the body, and as if it pushed up and away along with it, at op- 
posite ends, a few of the outer vesicles, carrying them scattered on its 
surface, thus giving such an example a very singular appearance. 
I have not been able to see the inception of food, but have noticed 
the ejection of crude, presumably indigestible, matter, such as, seem- 
ingly, the skin or wall of some protococcoid. This is effected by a some- 
what sudden effort, looking, at first sight, hke a breaking into two of 
the rhizopod itself, but it is only the turning out or eversion of the 
undigested rejectamenta. However, during this act of what may be 
called defecation some of the colouring granules are likewise simulta- 
neously ejected, and a few of the outer vesicles thrown off; this, of 
course, accidental and seemingly caused by the mechanical action in- 
volved in the effort. The creature does not seem to suffer by this loss 
of a portion of its substance; it shortly reassumes its orbicular figure, 
and shows no change except the certain small amount of loss of colour, 
just as in the example subjected to artificial pressure before described. 
Of all actinophryan or ‘‘radiolarian”’ forms that I have seen this 
appears to me to possess the greatest amount of locomotive power— 
next to it in this respect, perhaps, comes the form I have previously 
mentioned under the name of Heterophrys Fock. The present form 
often makes very decided changes of place as it is viewed under a 
quarter-inch. It seems occasionally to be able to roll along with a cer- 
tain slow and undecided but perceptible amount of vigour, as if its 
slender but hardly evident pseudopodia performed the part of ambula- 
tory organs; but at other times no motion or change of place at all is 
noticeable. 
As in other Rhizopods which present a distinct coloration, it must be 
presumed that the intensity of the reddish or garnet colour, inclining 
to purple, characteristic of this species, is due to condition of nutrition. 
Examples presenting themselves in gatherings kept for some time in 
the house are paler in colour than those met with in fresh and healthy 
gatherings, which abound with other forms of animal and vegetable 
life. Still, though paler and fewer, the reddish granules seem never 
to be wholly absent. Such examples, too, besides the pale colour, 
likewise show the outer vesicles, not only fewer, but seemingly more 
or less diminished in size, or shrivelled and collapsed; but I have not 
seen specimens from which they were absent, though they may have 
lost their spherical bubble-lke appearance. 
VOL. ¥. 21 
