$$ 9, 10. 25 
tical action of the water. But with others the locomotive organ is a long 
retractile proboscis.” With the Oxytrichina and Euplota, there are 
fleshy movable points (uNcINI) upon the ventral surface, by which these 
animals move about as upon feet. During these movements with the Oxy- 
trichina, the posterior portion of the body is supported by many setose 
-and styloid processes, which point backward. 
The singularly varied and branching locomotive organs of the Rhizo- 
poda are short, and digitated with Ameba, Difflugia and Arcella.” But in 
the other genera they are elongated and filamentous. 
INFUSORIA AND RHIZOPODA. 
t 
CHAPTERS III. AND IV. 
NERVOUS SYSTEM AND ORGANS OF SENSE. 
: § 9. 
Although the Infusoria clearly evince in their actions the existence of 
sensation and volition, and appear susceptible of sensitive impressions, yet 
no nervous tissue whatever has as yet been found in them. If Ehren- 
berg supposed the Polygastric Infusoria to possess a nervous system, he 
did so because, having decided that the red pigment points of these ani- 
mals were eyes, he inferred that they necessarily had a nervous ganglion 
at their base. 
§ 10. 
With the naked Infusoria the sense of touch exists, undoubtedly, over 
the whole body. But beside this, it appears specially developed, in many 
species, in the long cilia forming vibratile circles, or in those movable 
foot-like and snout-like prolongations of the body. In the same manner, 
it is probable they have the sense of taste also; for they seem to exercise 
a choice in their food, although no gustatory organ has yet been found. 
All species, whether they have red pigment points or not, seem affected by 
light. Without doubt, therefore, their vision consists simply in discrimi- 
nating light from darkness, which is accomplished by the general surface of 
the body, and without the aid of a special optical organ. 
The simple pigment point of many Infusoria,® and which Ehrenberg has 
generally regarded as an eye,” has no cornea, and contains no body capa- 
ble of refracting light; there is, moreover, connected with it no nervous 
substance. 
Ehrenberg attaches here too great an importance to the red color of the 
8 Amblyophis, Euglena and Peridinium, have 
a simple flagelliform cilium, but with Chlorogo- 
nium it is double. 
4 Trachelius trichophorus feels about with a 
long snout of this kind, without, however, produc- 
ing a vortical action on the water. 
5 See Ehrenberg, “Die Infusionsthierchen,” 
Taf. VIII. and IX. . 
6 Gromia fluviatilis, Miliola vulgaris, Vor- 
ticialis strigilata, Euglypha tuberculosa, Tri- 
nema acinus, according te Dujardin (Ann. des 
Se. Nat. Zool. IV. 1835, p. 343, pl. IX.; also, V- 
1836, p. 196, pl. IX. fig. A. See, also, his Histoire 
des Infusoires, 1841, p. 249, pl. I. fig. 14-17; pL 
II. fig. 1, 2, 7—10 ; pl. TV. fig. 1); Geopvonus stel- 
la borealis, Nonionina germanica, according to 
Ehrenberg. Abhand. d. Berliner Akad. 1839, 
p. 106, Taf. I. IL. 
1 Amblyophis, Euglena, Chlorogonium, &c. 
2 AbhandJ. d. Berliner Akad. 1831, p. 12; alsc, 
“ Die Infusiousthierchen,” p 491. 
