Description of New Protozoa^ 
33 
jelly. It then immediately proceeds to multiply itself in 
geometrical proportion by fissure until masses are formed, 
which, under favourable circumstances, attain a diameter of 
three or four inches, and consist of aggregations of many 
thousands of zooids. In this Protozoan the division is not 
complete; the zooids are united by fine threads, which permeate 
the gelatinous mass, and are homologous with the stalks of 
Epistylis. These threads also appear to have the property of 
transmitting nervous impressions through the whole mass of 
this compound animal, and rendering the movements of the 
associated zooids consentaneous. 
-When in England some years ago, I found in one of my 
fresh-water aquariums a great number of specimens of Sten- 
tor MiUleri, each one of which was surrounded at its base by 
a flocculent deposit similar in structure to the lorica of OpJi- 
rydium versatile, and into which the animal could withdraw 
itself. At first I considered that this state was the result of 
disease, but further experience showed that the deposit was 
never absent. Many of the animals inhabited a tall gelati- 
nous pillar, by which they raised themselves considerably 
above the surface on which they grew (fig. 11). Others by fis- 
sure had formed colonies, which were attached to the glass, or 
hung downwards while floating on the surface of the water ; 
others, again, were swimming naked in search of sites for fu- 
ture erections ; but no fixed animals were found to be destitute 
of a lorica. I have repeatedly met with this animal since, 
and always in the same loricated state. 
In the summer of 1857, a small species of Stentor, of a 
deep chestnut colour, occurred in the pond of the Edinburgh 
Botanical Gardens, which is in the habit of secreting a lorica 
like that of Stentor Millleri. This species, which I have 
called castaneus, selects the tips of the shoots of Myriophyl- 
lum for its abode, and glues all the opening leaflets together 
with a mass of jelly, from which the zooids protrude their 
wheel-bearing heads. The possession of a lorica removes 
Stentores Millleri and castaneus from the family Vorticellina 
to that of Ophrydina, which (says Ehrenberg) includes true 
Vorticellse or Stentors inclosed in a gelatinous membranous 
little box" or shell. In the last family, a new genus will 
VOL. II. E 
