42 MANUAL OF ZOOLOGY SECT. 



of two other ways, or in both of them. Many take in 

 minute solid particles of organic matter, usually in the form 

 of minute living organisms. In many such cases there 

 is, as in Euglena, an aperture, the mouth, opening into a 

 short passage, the gullet, by which the food is received into 

 the protoplasm in the interior of the body ; but this is not 

 always present, and in such cases (Fig. 13, 8) the food parti- 

 cles are taken in by a process not unlike that which we have 

 seen to occur in Amoeba. But, on the other hand, many of 

 the Mastigophora are not distinguishable from plants in their 

 mode of nutrition ; and on that ground, taken in connection 

 with their structure, which is in nearly all respects that of 

 a typical unicellular plant, have almost equal claims to be 

 ranked in either the vegetable or the animal kingdom. 

 They have a cell-wall of cellulose like a plant cell, they 

 contain chlorophyll or a red colouring matter, hamatochromt, 

 of similar composition, and they have no mouth. They 

 must, therefore, be nourished precisely after the manner 

 of a green plant, and, if they are assigned to the animal 

 kingdom instead of to the vegetable, it can only be because 

 the possession of flagella seems to ally them with forms that 

 are of undoubted animal character. 



Colonies are of frequent occurrence among the Mastigo 

 phora. Sometimes there is a branching slender stalk- 

 bearing a single zooid or a group of zooids at the end of 

 each of the branches (Fig. 14, j), the whole colony being 

 fixed by the base of the main stalk, and the flagellum serving 

 for the capture of food-particles and not for locomotion. 

 Sometimes (Fig. 17) the colony is of a more massive charac- 

 ter, the zooids being embedded in a clump of gelatinous 

 material, with the end bearing the flagellum projecting on 

 the exterior : usually such colonies are free-swimming. 



Multiplication is effected most commonly by the simple 



