ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 331 



Atlantic. The interest of the laro-e memoir is mainly systematic, hut 

 the introductory chapter proposing a classification hased on the characters 

 of the nutritive polyps is of wider interest. J. A. T. 



Asexual Multiplication of Microhydra ryderi. — A. Goette {ZooL 

 Anzelfjer, I'.C^u, 51, 71-7, 8 figs.). The frustules of this polyp are true 

 buds, which are separated off from the mother-animal by a process of 

 division. The longitudinal division which separates off a frustule- 

 primordium, and the transverse division by which the two halves of the 

 laterally fixed frustule are separated from one another, are conditioned by 

 a divergent growth-movement and a divergent correlation. J. A. T. 



Protozoa. 



Crystalloids of Entamoeba histolytica. — Akmaxd Dehorne {Arch. 

 ZooL Exper., 1910, 58, Notes et Revue, 11-8, 4 figs.). In this Amoeba, 

 associated with abscesses of the liver, there are abundant spindle-shaped 

 crystalloids which appear in vacuoles in the endoplasm. They corre- 

 spond to chromidia. The crystalloids are ephemeral ; they disappear or 

 are much reduced when the cyst-envelope is formed. Protozoa with 

 shells or capable of forming cysts have an important chromidial apparatus, 

 and this is causally related to forming the shell or cyst. The crystalloids 

 represent a stage in the metabolism that leads to shell-making. Perhaps 

 trichocysts are similarly related to memljrane-making. Perhaps every 

 chromidial apparatus has this significance. J. A. T. 



Nucleoplasmic Relations in Arcella. — R. AY. Hegner {Jouni. 

 Exper. ZooL, 1020, 30, 1-96, 47 figs.). The data gathered from a study 

 of four species favour the hypothesis that there is normally a definite 

 quantitative relation between nucleus and cytoplasm. In both binucleate 

 and multinucleate specimens the nuclei, although free to move about in 

 the cytoplasmic mass, become arranged in such a manner that they are 

 equidistant from one another, and hence Lave each an equal amount of 

 cytoplasm with which to interact. Many micro-vivisection experiments 

 bear out the idea of a constant mass relation between cytoplasm and 

 nucleus. An excess in the amount of cytoplasm in proportion to nucleo- 

 plasm appears to be dangerous. The final conclusion of an important 

 investigation is that the size of the organism and the characteristics 

 correlated with size are dependent upon the chromatin mass ; that changes 

 in these characters are not due to cytoplasmic nor chromidial influence, 

 but to qualitatively unequal nuclear divisions, resulting in two types of 

 daughter nuclei differing in the determiners that control the growth of 

 the chromatin ; and that other characters that vary independently must 

 be controlled by other determiners within the nuclei. J. A. T. 



Chilomastix mesnili of Man.— Charles A. Kofoid and Olive 

 SwEZY {Univ. CaUfornia Puhlications, Zoology, 1920, 117-44, 3 pis., 

 2 figs.). In the human intestine this is a common and widely distributed 

 parasite often mixed up with Trichomonas and other forms. It has a 

 deep spiral groove running posteriorly from right over to left as a 

 permanent cell-organ distinct from but adjacent to the cytostome. It 



