322 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
large part of the world. Among these is a new genus, which he calls 
Maupasia paradoxa, from the Sandwich Islands. The anterior fourth of 
the ovoid body is provided with long cilia, which apparently have no 
definite arrangement, while the rest of the body is covered with long 
plasmatic filaments, which are much stronger than the cilia, and resemble 
flagella. At the hinder end of the body there is a still longer flagellum. 
It seems to him clear that the simultaneous possession of cilia and 
flagella makes Maupasia a form intermediate between the Infusoria and 
the Mastigophora. This intermediate group may be called the Mastigo- 
tricha. Unfortunately, like other remarkable tropical intermediate 
forms, this type has not been seen again. In the second part of his 
work the author gives an account of the literature of the fresh- water 
Protozoa as yet observed in Europe. He comes to the conclusion that 
we cannot say that these Protozoa have a definite geographical distribu- 
tion, for they seem to be ubiquitous. Of the forms known from Europe, 
a large percentage have already been found beyond its boundaries. It 
is likely that species which have been found outside Europe will in 
time be found also in it. 
Food Vacuoles in Infusoria.* — Miss M. Greenwood discusses the 
constitution and mode of formation of food vacuoles in Infusoria, as 
illustrated by the history of the process of digestion in Carchesium 
polypinum. She finds that this Vorticellid offers in many ways a par- 
ticularly good field for the study of some of the processes of protozoan 
digestion. Ingestion is often eager ; digestion may be rapid ; and the 
especially transparent cell- substance which characterises this animal 
allows of the observation of both. One striking feature after the 
administration of abundant nutriment is the presence of numerous 
spherical masses of food. These may number 100 in one polype of 
Carchesium. Continued watching shows that each spherical food-mass 
springs from one vacuole of ingestion. The vacuole discharged from 
the oesophagus internally, and made up of water and, as the case may 
be, amorphous matter, motile particles, or inert particles, passes towards 
the base of the animal. It pauses internally at the curve made by the 
nucleus in this region, and without further locomotion or, after slight 
rotary movement, the finely divided solids which it contains undergo 
a sudden and striking rearrangement. All the granules present are 
shifted centripetally, all individual movement is stilled, and a composite 
solid lying in clear fluid surroundings, represents the scattered particles 
of a moment ago. The food-masses thus welded journey through the 
substance of Carchesium in a fairly constant fashion, but for a variable 
time. Digestion may take place at any point throughout a relatively 
large part of the central substance of Carchesium , but the region from 
which insoluble matter is rejected is, like the place of ingestion, definite. 
A vacuole of ingestion passes into the protoplasm from the extreme 
internal point of the oesophagus. Effete matter is passed into the 
pharynx at the junction of its external and middle thirds from some spot 
in a ridge running transversely to the long axis of the polype in that 
region. Ingestion of matter by Carchesium is indiscriminate ; when the 
Phil. Trans., clxxxv. B. (1894) pp. 355-83 (1 pi.). 
