February, 1920] GENETICS 39 



267. Lots y, J. P. Over de mogelijkheid van intranucleairekruisingbij homozygoten. [On 

 the possibility of intranuclear crossing in homozygotes.| Genetica 1 : 02 97. tO fig. Jan., 

 1919. — Author shows that when in reduction-division, the chromosomes, combined into a 

 thread, are parting again, there is a ceil. Lin hypothetical possibility of "chromosome-cross- 

 ing." Normally the thread breaks up into Bame pieces (chromosomes) which were united 

 in the dividing nucleus, but it might happen that one chromosome carry with it a chromo- 

 mere of the chromosome with which it was united. Thus normal chromosomes A, B, C would 

 become by this process A+, B— , C. The gamete which contains this new set of chromosomes 

 will very probably unite with a normal one giving a hybrid with exactly the same number 

 of identical chromomeres as the homozygous plants, only combined in this way: AA+ BB — 

 CC. This hybrid plant would appear exactly like the homozygous plants but would produce 

 four classes of gametes: ABC, AB — C, A+BC, and A+B — C. When selfed F 2 plants will be 

 as follows: 6 plants with same number of chromomeres; 4 plants with one chromomere less 

 than normal; 4 plants with one chromomere more than normal; 1 plant with two chromo- 

 meres less than normal (recessive mutant) ; 1 plant with two chromomeres more than normal 

 (progressive mutant). Both recessive and progressive mutant when crossed with normal will 

 segregate in F2 in 3 : 1 ratio. Author thinks this is in fair accord with cases in which mutants 

 arise in pure strains. There is no formation of genes in the progressive mutant and thus no 

 mutation as the process is understood by De Vries. Author remarks that crossing of individ- 

 uals is also necessary for production of new types. Organisms having only non-sexual prop- 

 agation have no mutative power in this way. — //. N. Kooiman. 



268. Lotsy, J. P. Bestendige Bastaardes. [Constant hybrids.] Vereeniging tot bevor- 

 dering van wet. teelt 1918 (No. 10): 1-42. 1919. — Chiefly a more popular presentation of matter 

 in author's article on De Oenotheren als kernchimeren [The Oenotheras as nuclear chimeras] 

 [See Bot. Absts. 3, Entry 52], but differs in that author accepted the existence of chrom- 

 omeres within the chromosome in the mentioned paper while in present paper the chromo- 

 some is treated as an indivisible unit. — At the end he discusses origin of sex and of bisexual 

 animals in normally unisexual species in connection with knowledge of the so-called X and 

 Y chromosomes. — H. N. Kooiman. 



269. MacCaughey, Vaughan. Race mixture in Hawaii. Jour. Heredity 10:41-47. 

 Jan., 1919. — Asiatics comprise nearly three-fifths of the population of Hawaii, Polynesians 

 less than one-fifth, pure Hawaiians only about one-tenth, mixed Caucasian-Hawaiians and 

 Chinese-Hawaiians about another tenth. In Hawaii Japanese marry only Japanese, but 

 only a little more than half of the Chinese men marry Chinese wives. In general race mix- 

 ture is proceeding at a rapid rate. The article is accompanied by five tables giving statistics 

 in reference to race and marriage. The analysis includes not only pure races, but the mar- 

 riages of persons of mixed blood. — H. H. Laughlin. 



270. Maxon, William R. A new hybrid Asplenium. Amer. Fern Jour. 8: 1-3. 1918. — 

 See Bot. Absts. 2, Entry 344. 



271. Meader, Percy D. Variation in the diphtheria group. Jour. Infect. Diseases 24: 

 145-157. 1919. 



272. Mendiola, Nemesio Blanco. Variation and selection within clonal lines of Lemna 

 minor. Genetics 4: 151-182. 6 fig. Mar., 1919.— See Bot. Absts. 3, Entry 101",. 



273. Meyer, Adolf. The right to marry; what can a democratic civilization do about 

 heredity and child welfare? Mental Hygiene 3: 48-58. Jan., 1919. — See Bot. Absts. 3, 

 Entry 2172. 



274. Murbeck, Sv. En saregen blomanomali hos Capsella bursa-pastoris. [Abnormal 

 flowers in Capsella bursa-pastoris.] [Swedish, with German summary.] Ark. Bot. 15 (No. 

 12) : 1-S. 1 fig. July 25, 191S. — A very large individual of Capsella bursa-pasloris was found 



