PROTOZOA. OF HERTFORDSHIRE. 
97 
that the creatures obtain their food. Mr. Saville Kent, in his 
‘ Manual of the Infusoria,’ describes the process so beautifully that 
I think I cannot do better than quote the passage. “Whirling 
round with inconceivable rapidity, the flagellum creates a strong 
centrifugal current in the water, setting in behind towards the 
direction of its own apex, and bringing with it all such tiny particles 
as do not possess sufficient power or weight to stem its tide ; but 
for the outstretched collar, these would simply hurry with the 
stream past the monad’s body. Hot for them, however, so easy a 
passing of the rapids. In the midst of their swift career they 
strike against the almost impalpable film of sarcode of which the 
organ is composed, and to this they adhere as tenaciously as a 
snared bird to a lime-daubed twig, or an incautious fly to a spider’s 
web. Then slowly, almost imperceptibly, the captive atoms are 
carried up the outside and down the inside, until, reaching the base 
of its inner surface, they are engulfed within the sarcode substance 
of the monad’s body.” The particles thus taken into the body 
gradually accumulate into spherical masses in the same manner 
as in the Yorticellidae, and the undigestible particles are eventually 
ejected from the same area wherein they were originally in¬ 
cepted. 
The other features, e.g. the nucleus, and the contractile vesicles, 
were fully treated of in my previous paper on the section Panto- 
stomata ; there is therefore no necessity for further remark on these 
points. Although great similarity of shape exists in the bodies of 
the animalcules, yet in their loricae or protective envelopes we find 
great diversity; all are of exquisite form and contour, often exactly 
resembling the amphorae, lachrymarise, or the tear-bottles and other 
vases of ancient Greece. 
After the above brief description of the anatomy of the collared 
monads, little remains but to mention and describe those species 
which have come under my observation. 
We must of course take them in the order of classification, which 
divides the section into three families. The first, called Codo- 
hosigidh:, includes all those species which are naked, i.e. which 
secrete no protective envelope; the second, Salpihgkecidjs, 
embraces those forms which secrete a lorica; and in the third, 
Phalatjsteridae, we find the animalcules associated and secreting 
a gelatinous mucus which forms extensive colonies. 
The first family, Codohosigidae, is subdivided into four genera: 
Monosiga, in which the animalcules are solitary and isolated; 
Codosiga , which includes all which are united socially in a cluster 
on a common pedicel or stalk; Astrosiga, so called from the stellate 
form of the groups, which swim freely through the water; and 
Desmarella , so called from the chain-like form of the clusters. 
I have found several species of the first genus, Monosiga. Pirstly, 
M. consociata , which, as the name implies, is of gregarious habits. 
It was found upon a confervoid filament, attached, not by a 
footstalk or pedicel, but by merely resting upon the weed, a fre¬ 
quent mode of attachment technically termed sessile ; the monad is 
