Bauhaus-Universität Weimar

Titel:
The Cyclopaedia of Anatomy and Physiology, vol. 4: Pla [corr.: Ple] - Wri
Person:
Todd, Robert Bentley
PURL:
https://digitalesammlungen.uni-weimar.de/viewer/image/lit29465/22/
12 POLYGASTRIA. 
observer. These beautiful little creatures might 
be compared to wine-glasses of microscopic 
dimension, the bells of which are fixed to 
highly irritable stems, that are attached by 
their opposite extremity to some foreign body. 
These stems are endowed with the capability 
of extending themselves in the shape of straight 
filaments of exquisite tenuity, and on the 
slightest alarm or irritation, of shrinking into 
close spiral folds, so as to draw the little bell 
as far as possible from danger. The mouth of 
the bell is fringed with a circlet of cilia, which 
vibrate rapidly at the pleasure of the animal, 
causing a magnificent whirlpool in the sur¬ 
rounding water, which brings nutritious sub¬ 
stances that may be in the neighbourhood 
towards the oral orifice, the situation of 
which is nearly the same as in Stentor, above 
described, and thus the little being is abun¬ 
dantly supplied with food. The true Vorti¬ 
cellæ, although generally found grouped toge¬ 
ther in elegant bunches, always have single 
undivided stems ; but in the genus Carcfiesium, 
the animals of which are similarly organised, 
the pedicles sprout from one another so as to 
have a branched or ramose appearance, while 
in the genus Epistylis, animals similar to Vor- 
ticella and Carchesium are met with, the stems 
of which are quite stiff and inflexible, so 
much so indeed that the animalcules belonging 
to this group have obtained the name of “ pil¬ 
lar bells ” (Saulenglöckchen). 
The family Ophrydinidœ presents us again 
with very remarkable forms of Polygastric ani¬ 
malcules, allied in structure to the Vorticellæ, 
but having their bodies inclosed in cases of 
different kinds, of which it will be necessary 
to give one or two examples. 
The genus Ophrydium, (jelly-bell-animal¬ 
cules,) of which the Ophrydium versatile (fig. 
10) is an example, was regarded by the older 
Fig. 10. 
Section of a portion of the periphery of Ophrydium 
versatile, showing the manner in which the individual 
animalcules are implanted in the mass. 
naturalists as being a mass of vegetable matter, 
and had the names of ulva, fucus, conferva, &c. 
conferred upon it by different authors, until 
Miiller, in 1786, first announced its real nature 
and relationship to the vorticelline animalcules. 
It is found under the shape of a gelatinous 
mass of a lively or dull green colour, which in 
consistence may be compared to frog’s spawn, 
some specimens attaining the size of four or 
five inches in diameter; the whole forming an 
irregularly shaped but smooth mass, which is 
composed of many millions of distinct animal¬ 
cules, each about jfeth of a line in thickness, 
and about the -^th of a line in length. The 
space of a square line would therefore contain 
9216 of these diminutive beings; a cubic line 
six times as many, or 55,296; and a cubic 
inch nearly eight millions, namely, 7,962,624. 
In the water all these congregated animalcules 
are disposed in close rows, something in the 
same manner as in Volvox. On shaking the 
mass many others show themselves within be¬ 
tween the former, so as to form from three to 
five different ranks. At first all the gelatinous 
cells appear to be connected with the centre of 
the mass by filamentary prolongations, but these 
disappear as they proceed internally, so that 
the middle seems to be hollow and full of 
water; the whole, indeed, might be compared 
to the gelatinous polyp masses (Alcyonidæ) 
found upon the sea-shore, only the structure of 
the animalcules is polygastric and not that of 
polyps. 
In the other genera belonging to the family 
Ophrydinidæ, namely, Tintinnus, Vaginicola 
(9, fig. 11,) and Cothurnia, although living in 
gelatinous transparent sheaths, and resembling 
Vorticellæ in their structure, are not associated 
in masses, but remain permanently detached 
and solitary. 
The family Encheliadæ contains various 
forms of animalcules, having the oral and anal 
orifices distinct and situated at the opposite 
extremities of the body. The different genera 
of which it is composed may be distinguished 
as follows :— 
Enchelis, (revolving animalcule,) has its 
body flask-shaped, (,\,fig> 11,) without any 
cilia externally, but with a circlet around the 
mouth, which is suddenly truncated and desti¬ 
tute of any dental armature. 
Disoma, (double-bodied animalcule,) crea¬ 
tures nearly resembling Enchelis in form and 
structure, but with a double body (6,7,fig. 11). 
Act inop hrys, (sun animalcule,) having the 
exterior of the body unprovided with loco¬ 
motive cilia, but stuck over with setaceous ten- 
tacula which radiate in all directions. 
Trichodiscus, (radiated disc animalcule,) re¬ 
sembling Actinophrys, only the body is here 
Fig. 11. 
1, 2, 3, 4, 5. Enchelis farcimen, swallowing food. 
6, 7. Disoma vacillans. 8. Lachrymaria proteus, 
9. Vaginicola decumbens.
        

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