ZOOLOGY AND BOTANY, MICllOSCOPY, ETC. 207 



:solutioii and then returned to a normal medium regain the fission rate, 

 size, spine length, and colour characteristic of the race. Specimens 

 grow and reproduce in a medium with 0*25 to 1 p.c. of alcohol, but the 

 alcohol is injurious, as indicated bj the retarded fission rate and irregu- 

 larities in the shells of the off'spring. Lowering the temperature seems 

 to lead to reduction of the length of the spines. Wild specimens of 

 A. polypora with a bent oval shell with an oval mouth gave rise in 

 laboratory conditions to offspring with a flat circular shell and a circular 

 mouth opening. It appears, then, that modifications induced by environ- 

 mental peculiarities persist only so long as the modifying factors are 

 operative. Xo heritable diversities were observed that were due to the 

 changed conditions. J. A. T. 



Intestinal Protozoa in Members of Egyptian Expeditionary Force. 

 — F. ^\. OX'ONNOR {Parasitology, 11)19, 11, 239-55, 1 pL, 3 figs.). 

 Report dealing Avith Entammha histolytica, E. coU, Trichomonas hominis, 

 LamUia intestinalis, ^' Entamoeba ^^ nana, Tricercomonas and Isospora 

 hominis. J. A. T. 



Race of Oxytricha without a Micronucleus. — J. A. Dawson 

 {Journ. Exper. ZooL, 1919, 29, 473-513, 2 pis.). A pedigreed culture 

 of Oxytricha hymenostoma was kept up for 289 generations (from 

 July 10, 1917, to April 30, 1918), and no micronucleus was seen. Nor 

 was there any true conjugation or syngamy. Individuals fused in pairs 

 in a manner similar to that of conjugating individuals, and remained 

 fused till death occurred, or else separated and went on multiplying. 

 Catmibalism was frequent and digestion rapid. Cannibalism has the 

 effect of raising the division rate somewhat for a short time. The 

 amicronucleate condition seems to preclude the occurrence of conjuga- 

 tion, autogamy, and endomixis ; yet without these the race flourishes in 

 favourable environmental conditions. J. A. T. 



Structure of Noctiluca. — Charles A. Kofoid (JJniv. California 

 PuUications, Zoology, 1920, 19, 317-34, 1 pi., 2 figs.). A new inter- 

 pretation is offered, that Noctiluca is a dinoflagellate highly modified 

 through distention by hydrostatic vacuoles. It retains the dinoflagellate 

 sulcus, modified anteriorly into the apical trough and the recessed oral 

 pouch and cytostome. Of the girdle only the proximal part persists ; it 

 has been hitherto overlooked. It is a shallow trough at the left of the 

 sulcus and at right angles to it. It is best seen in small individuals. 

 With the degeneration of the girdle has gone the reduction of the trans- 

 verse flagellum to the prehensile tooth which lies at the proximal end of 

 the girdle at the left of the base of the longitudinal flagellum. This 

 organ exhibits structural undulations and spasmodic and rhythmical 

 contractions. The longitudinal flagellum is reduced and lies within the 

 oral pouch. It is the distention with hydrostatic vacuoles, with flotation 

 replacing active locomotion, which has led to the degeneration of the 

 flagella and their reduction in size, and to the almost complete disappear- 

 ance of the girdle. The posterior tentacle is the homologue of the 



