No. 1, July, 1920J GENETICS 07 



atioo from nucleated pari by Bmaller daughter cell bu1 original size for clone is regained in 

 granddaughter cell. Portions may be removed repeatedly bul as long .-is some of shell remains 

 with nucleus and cytoplasm progeny will eventually regain charaoti typical for done. 



Removal of part of chromidial net was without perceptible after-effect in these experiments. 

 Bisection of binucleate specimens 15-spined and 35 units in diameter led eventually to uni- 

 nucleate clones averaging 11 spines and 25 units in diameter; uninucleate condition usually 

 persisted for from 6 to 33 generations. Return to binucleate condition occurred with empty 

 cell formation, nuclear doubling seeming to have been initiated when cytoplasmic mass be- 

 came greater i han quant it y normally associated with one nucleus. Resl oral ion of binucleate. 

 status was gradually followed by cytoplasmic increase until after 3 or 4 generations nucleo- 

 oplasmic relation of original binucleate line was attained, that is, a single great internal 

 change is paralleled in soma by scries of small changes in a definite direction (orthogenetic 

 variation apparently). Observations of small changes, gradually accentuated in successive 

 generations, in other protozoa can be interpreted as due to single discontinuous genotypic 

 change only slowly influencing soma. In both uninucleates and binucleates- there is a corre- 

 lation between spine number and shell diameter of over 40 per cent. Two binucleate clon< ■ 

 differed in shell diameter and larger was found to contain larger total mass of chromatin in 

 each specimen than smaller. — In Arcclla polypora examination of 51 wild specimens showed 

 that nucleus number ranged from 3 to 10 with modal number 5; correlation between nuclear 

 number and shell diameter among these wild individuals was low (0.156±0.089). Diameters 

 of different clones with same number of nuclei might differ; specimens of clone apo, the diam- 

 eters of whose members was large in comparison with number of nuclei, had large chromatid 

 masses, while those of clone ap34, where the individual diameters were small compared to 

 number of nuclei, possessed smaller chromatin masses. Within one large clone (family apo) 

 selection for large and small diameters was successful but the small-diametered sub-clone was 

 found to be 4-nucleated while the larger-diametered sub-clone had 5- or 6-nucleated cells; in 

 general wdthin this clone there was a high correlation of diameter and number of nuclei (0.81 

 ±0.023). — Arcclla discoides resembled A. dentata in showing a smaller range of variation than 

 A. polypora, which is associated with a constancy of nuclear number in first two species (2 

 nuclei in each). Biotypes of A. discoides with different average diameters were isolated 

 from nature. Uninucleate specimens made by bisecting revealed relationships similar to 

 those reported for A. dentata when compared with binucleates. — In A. vulgaris shapes as well 

 size distinguished lines isolated from nature; variability resembled that in A. dentata and .4. 

 discoides. — Brief survey of development of conception of nucleo-cytoplasmic relation and of 

 chromatin-cytoplasmic relation is presented and bearing of Arcella results is indicated. — 

 James P. Kelly. 



603. Heinrich, M. Der Einfluss moderner Reinigungsanlagen auf die Giite des Saatguts. 

 [The influence of modern cleaning devices on the goodness of the seed.] Zeitschr. Pflanzen- 

 ziicht. 7: 19-30. 4 fig- June, 1919.— Shows use of modern cleaning devices with oats increases 

 test weight, purity, percentage germination, and percentage strong healthy seedlings. — F red 

 Griffee. 



604. Hennings, Hank. Mnemelehre oder Tierpsychologie? [The mneme theory or ani- 

 mal psychology?] Biol. Zentralbl. 39: 187-192. April, 1919. 



605. Herl. ant, Maurice. Comment agit la solution hypertonique dans la parthenogenese 

 experimentale (Methode de Loeb). I. Origine et signification des asters accessoires. [How 

 the hypertonic solution acts in experimental parthenogenesis (Method of Loeb). I. Origin and 

 significance of the accessory asters.] Arch. Zool. Exp. et G6n. 57: 511-533. Nov., 1918. — 

 Hypertonic solutions cause artificial parthenogenesis in sea urchin eggs by providing accessory 

 asters. Monasters produced in activated egg before application of hypertonic solution are 

 ineffective; accessory asters make efficacious bipolar mitosis possible. Capacity of solution 

 for causing development of eggs depends on concentration and composition. NaCl, KC1, 

 and OH ions favor accessory asters; CaClj and MgCls are neutral or inhibitory; II ions, KCN, 



BOTANICAL ABSTRACTS, VOL. IV, NO. 1 



