C. DOBELL 163 



structure happens to occupy on the parent at the moment of fission. 

 In some cases the abnormality disappears owing to remodelling during 

 successive generations : in other cases the abnormal forms die. Normal 

 sisters of abnormal forms show no tendency to beget correspondingly 

 abnormal individuals. Such teratological variations are therefore 

 negligible as factors in the production of new races. 



88. Additional information about ciliate monsters will be found in 

 the following papers: Balbiani (1891) — double monsters in Stentor ; 

 Balbiani (1892, 1893) — various monsters resulting from mutilation of 

 Paramecium, Stentor, etc.; Simpson (1901) and Calkins (1904) — 

 multiple monsters in Paramecium; Prowazek (1904) — double monsters 

 produced by cutting Stentor, etc.; Prowazek (1904 a) — Stylonychia mon- 

 sters with multiple hinder ends, resulting from " degenerative hyper- 

 regeneration " ; Calkins (1911) and Peebles (1912) — multiple and other 

 monsters produced by cutting Paramecia. Hereditary behaviour of 

 abnormalities is hardly touched on in these papers. Yet an interesting 

 fact is several times reported' — namely, that remodelling when it does 

 not take place in a monster itself may occur in its offspring; so that 

 in certain cases at least monstrosity is a temporary manifestation — the 

 peculiarity of the individual and not of its race. This is in accord with 

 the conclusion reached in the preceding paragraph. 



89. Before leaving the events of the asexual period, I would 

 mention an interesting observation by Fermor (1913). The authoress 

 finds that reorganization of the nuclear apparatus may occur in Stylo- 

 nychia during encystment — without any sexual manifestations. In the 

 encysted animal, the meganucleus degenerates and disappears. The 

 micronucleus then separates into two parts — one of the products subse- 

 quently forming the new meganuclei, the other forming the new micro- 

 nuclei. Thus the organism which emerges from the cyst has undergone 

 a nuclear reorganization comparable with that which accompanies 

 conjugation (§ 5). Conjugation was never observed in the race of 

 Stylonychia studied. I know of no other similar observation-. 



' This occurred, for example, in one of the double Stentors described by Balbiani 

 (1891). 



^ It is possible, however, that a similar nuclear reorganization may occur at times in 

 unencysted, asexually reproducing organisms. Hertwig (1889) believed that such a process 

 ("parthenogenesis") occurred in Paramecium, and a similar suggestion of the occurrence 

 of " autogamy " in the same form has more recently been made by Woodruff (1908 a). 

 The matter requires fuller investigation. [Whilst this article is passing through the 

 press, an important announcement has been made by Woodruff and Erdmann ("Complete 

 periodic nuclear reorganization without cell fusion in a pedigreed race of Paramecium," 

 Proc. Soc. exp. Biol, and Med., Vol. xi. No. 3, 1914, p. 73), The authors state that they 



