452 LORANDE LOSS WOODRUFF AND RH. ERDMANN 



The last period of the ascending phase is characterized by the 

 disappearance of all chromatin bodies. Figure 25 (pi, 3), Line 

 VIb, represents an animal, after the first cell division following 

 the origin of the macronuclear anlagen, showing two micronuclei 

 at the left, twenty chromatin bodies and several large vacuoles. 

 A single new macronucleus is visible. The other macronuclear 

 anlage, of the two in the parental cell, has been distributed to 

 the sister cell which was kept to continue Line VIb. This method 

 of distribution of the two macronuclear anlagen to each of the 

 new animals is the same as in typical conjugation of Paramaecium 

 aurelia. Maupas ('89, p. 222, pi. 13, figs. 23-27) gives a full 

 account of this distribution. Hertwig^'89, p. 38) shows that one 

 of the products of each of the two dividing micronuclei becomes 

 a macronuclear anlage and the other a micronucleus, but this 

 is not evident from his figure (pi. 3, figs. 9 and 10). The destruc- 

 tion of the old macronucleus occurs in most Infusoria during and 

 after conjugation by the formation of ribbon-like structures which 

 are finally resolved into chromatin bodies and disappear. This 

 is the method which obtains in Paramaecium caudatum and 

 Paramaecium aurelia (Maupas, Hertwig) and in Paramaecium 

 putrinum (Doflein). But the accounts of this stage given by 

 Maupas, Hertwig, and Calkins do not afford details of the ulti- 

 mate fate of the chromatin bodies, since they merely mention 

 that, by the formation of the daughter cells, these bodies decrease 

 in number and their remnants become pale and disappear in the 

 cytoplasm. Collin ('12, p. 223) however, gives a thorough ac- 

 count of the old macronucleus in Acineta papillifera and figures 

 (text-fig. 63) the gradual resorption of the chromatin remnants 

 in the cytoplasm. A different fate of the macronucleus was 

 observed by Ubisch ('13, p. 72) in a study of Lagenophrys, who 

 states that the chromatin bodies, which appear very similar to 

 micronuclei, are actually ejected from the macrogamete after 

 the formation of the syncaryon. The extruded chromatin bodies 

 were finally observed between the animal and its test. 



The total disappearance of the chromatin bodies in the reor- 

 ganization process of Paramaecium aurelia is thoroughly described 

 on page 455, It is distinguished from the similar stage in con- 



