112 



THE PROTOZOA 



i'.v 



FIG. 59. Division of Euglypha alveolate, 

 as seen in the living animal. 



A, Condition of the animal when about 

 to divide. The protoplasmic body shows 



three zones : (1) At the fundus of the shell is clear proto- 

 plasm containing the nucleus (N. ) and the reserve shell- 

 plates (s.p.) ; (2) the middle region is occupied by granular 

 protoplasm containing ingested food-materials {/.)and the 

 contractile vacuole (c.v.) ; (3) near the mouth of the shell is a zone of hyaline 

 protoplasm from which the pseudopodia (ps.) arc given off. 



B, Early stage of division, about twenty minutes later than A. The proto- 

 plasm is streaming out of the shell-mouth to form the body of a daughter- 

 individual, into which the reserve shell-plates are passing and arranging them- 

 selves at its surface to form a daughter-shell. In the nucleus chromosomes are 

 beginning to be formed. 



C, About twenty-five minutes later than B. The body of the daughter and 

 its shell are further advanced in formation ; in the nucleus of the parent the 

 equatorial plate is forming, and the two centrosomes are becoming visible on 

 the two flattened sides of the nucleus (the centrosomes are probably derived from 

 the division of the karyosome, no longer visible in the nucleus at this stage, or 

 from a centriole contained in the karyosome). [Continued at foot of p. 113.J 



