ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 593 



Garrey as " true chemotropism " is really due to the non-symmetrical 

 nature of the organism. Generally, Jennings is of opinion that Garrey's 

 results confirm and supplement his own. 



Galvanotaxis in Infusorians.* — Boris Birukoff observes that speci- 

 mens of Paramsecium, stimulated by induction currents, wander to the 

 cathode (as do dead particles of carmine and starch), but dispose 

 themselves in the parts of the water-drop where the strength of the 

 current is least, and arrange themselves similarly on the surface of the 

 electrode (which not-living particles do not do). Thus he contrasts 

 the purely physical and the vital. 



Nuclear Division in Noctiluca.f — Prof. C. Ishikawa has shown that 

 the division of the nucleus in this Protozoon takes place much in the 

 same way as in higher forms, the only difference consisting in the per- 

 sistence of the nuclear wall and the consequent modification in the 

 relative position of the spindle fibres and the chromosomes. He proceeds 

 to describe the centrosome, centrosphere, and pole-plate, especially 

 emphasising the remarkable resemblance of the archoplasm of Noctiluca 

 to the centrosphere of Metazoa on the one hand, and to the pole-plate 

 of less specialised Protozoa on the other. The relation of the archo- 

 plasm to the tentacle is next considered. In spore-forming individuals 

 the flagellum is developed from the archoplasmic spindle-fibres, just as 

 the tail of a spermatozoon is developed from the remains of the spindle- 

 fibres of the last division of the sperm-cells. Ishikawa now adds the 

 observation that a part of the centrosphere goes to form the tentacle. 

 He calls attention to the great interest of the fact that similar processes 

 are met with in the formation of the motile organ (cilia or flagella) of 

 the cells in Flagellata, Algae, Gymnosperms, and Vertebrates, wherein 

 the centrosome or the centrosome-like body plays the most important 

 part. Furthermore, the direct conversion of the central or archoplasmic 

 spindle-fibres into the flagellum of spores in Noctiluca is probably to be 

 looked upon as an interesting contribution to the knowledge of the 

 archoplasm. The author then discusses the elongation of the fibres of 

 the archoplasmic spindle, and, finally, abnormal multipolar division. 

 The abnormality clearly demonstrates that the kinetic centres of the 

 nuclear division in Noctiluca lie outside the nucleus and can form 

 spindles quite independently of it. 



Notes on Chrysomonads.f — Herr L. Iwanoff discusses the species 

 of Mallomonas (three being recognised as " good "), Chrysopyxis bipes 

 (which he followed through several phases), Uroglena volvox (whose 

 conjugation he regards as non-proven), Chromulina nebulosa, and Dino- 

 bryon spiralis sp. n. He regards all these as Algae. 



Rdntgen Rays and Protozoal — Herr F. Schaudinn subjected 

 members of twenty species to fourteen hours' exposure to these rays, 

 and describes the very varied results. Those with the least substantial 



* Pfluger's Arch. ges. Physiol., lxxvii. (1899) pp. 555-85. See Zool. Centralbl., 

 vii. (1900) p. 548. 



t Journ. Coll. Sci. Univ. Tokyo, xii. (1900) pp. 243-62 (1 pi.). 



t Bull. Acad. Imp. St. Petersbourg, xi. (18i)9) pp. 247-62. 



§ Pfluger's Arch., lxxvii. (1899) pp. 29-43. See Zool. Centralbl., vii. (1900) 

 p. 543. 



