412 



SCIENCE 



[N. S. Vol. XXVIII. No. 717 



The Chromosomes in Diahrotica vittata, Dia- 



hroiica soror and Diahrotica 12-punctata: 



N. M. Stevens. 



Diahrotica vHtaia has an unpaired hetero- 

 chromosome which, passes undivided to one 

 pole of the first spermatocyte spindle and 

 divides in the second maturation division. 

 Diahroiica soror and Diahrotica 12-punctata 

 have, in addition to the unpaired hetero- 

 chromosome, in about fifty per cent, of the 

 male individuals collected, one, two, three or 

 four small " supernumerary " heterochromo- 

 somes, the number being constant for the in- 

 dividual. The supernumeraries divide some- 

 times in the first, sometimes in the second 

 spermatocyte mitosis. 

 The Experimental Control of Asymmetry at 



Different Stages in the Development of the 



Lobster: Victor E. Emmel. 



In the adult lobster asymmetry of the 

 chelse is very stable and not subject to re- 

 versal, but in the first four larval stages it 

 was found that right or left asymmetry can 

 be produced at the will of the experimenter; 

 consequently it appears that the possibility for 

 experimental control of asymmetry is corre- 

 lated in some way with the degree of differ- 

 entiation or development of the organism. 

 These facts indicate that the factors control- 

 ling asymmetry become operative after the 

 organism leaves the egg, and that " right- or 

 left-handedness " is not necessarily a question 

 of " inheritance " or even of " alterations in 

 germinal organization." 

 The Physiological Basis of Restitution of 



Lost Parts: C. M. Child. 



The paper includes a discussion of Holmes's 

 hypothesis of form-regulation and a state- 

 m.ent of the writer's position regarding the 

 physiological basis of the process of restitu- 

 tion, which is that a lost part can be replaced 

 only when some other remaining part is 

 physiologically sufficiently similar to it to 

 perform its chief functions qualitatively if 

 not quantitatively, after its removal. 

 The Process of Heredity as exhihited hy the 



Development of Fundiilus Hyhrids: H. H. 



Newman. 



Heredity is conceived of as essentially a 



resemblance in developmental process be- 

 tween offspring and parents and is studied ex- 

 perimentally as such. 



In hybrids between these two species of fish 

 the earliest disturbances of the normal de- 

 velopmental process produced by the intro- 

 duction of foreign spermatozoa are noted, the 

 origin and rhythmic flux of characters are 

 studied, and attempts are made to get some 

 light on the ultimate physiology of the pro- 

 cess. Accompanying the paper are pictorial 

 tables showing the comparative developmental 

 processes of the two pure breeds and the re- 

 ciprocal crosses. 



Variation, Heredity and Evolution in Proto- 

 zoa. I. The Fate of New Structural Char- 

 acters in Paramecium, with Special Refer- 

 ence to the Question of the Inheritance of 

 Acquired Characters in Protozoa: H. S. 

 Jennings. 



The author followed the fate at reproduc- 

 tion of many new or " acquired " structural 

 characters, some produced experimentally, 

 some found in nature. These were not in- 

 herited. Sometimes such a character is 

 handed on bodily to a single individual of 

 each generation; one was thus followed for 

 twenty-two generations. But there is no 

 tendency for them to multiply and produce a 

 race bearing them. Such a tendency shows 

 itself only in the case of the very rare charac- 

 teristics arising from something permanently 

 modifying the process of fission. " The in- 

 heritance of acquired characters " takes place 

 no more readily nor generally in protozoa 

 than in higher organisms. 



LITHIUM IN RADIOACTIVE MINERALS'- 

 The question as to whether lithium is or is 

 not a widely occurring element, and whether 

 it is found associated with any other element, 

 more particularly with copper than with the 

 alkalies or the alkaline earths, arises from 

 the assumed transmutation of copper con- 

 tained in solutions, into lithium, neon and 

 possibly other substances. 



^Abstract of a paper by Professor W. N. Hart- 

 ley at the Dublin meeting of the British Asso- 

 ciation. 



