68 EDMUND B. WILSON 



nucleoli are visible in the same section are not very common. 

 Two such cases are shown in figs. Ik, L, each of which shows also 

 four of the nine larger bivalents. 



I have not endeavored to make an exhaustive study of the 

 growth-period as a whole, but the facts reported above taken in 



such a body is not present in the oocyte-nucleus, therefore the odd or accessor}' 

 chromosome of the male cannot be derived in fertilization from the egg-nucleus 

 an obvious non sequitur. Buchner's argument, based upon precisely opposite 

 data, shows a somewhat similar, though less obvious entanglement. The essence 

 of his objection is given in the following passage, which at the outset accepts 

 all the essential facts on which the conclusions of Stevens and myself were based. 

 "Auf alle Falle haben wir nur eine Sorte von Eiern, denn dasser (the accessory 

 chromosome) in einem Ei ausgestossen und im andern innenbehalten wird, er- 

 scheint undenkbar. Die Spermatozoen haben das accessorische Chromosom zur 

 Halfte. Nehmen wir an, die Eier besassen das accessorische Chromosom schon, 

 so gabe es Tiere mit zwei Monosomen und solche mit einem ein Fall der nicht 

 ezistiert" (op. cit., p. 409, italics mine). This is, indeed, an astounding statement; 

 for it was the very fact that there are individuals that have but one monosome 

 or accessory chromosome (the males), and other individuals of the same 

 species (the females) that have two corresponding chromosomes, upon which the 

 conclusions of Stevens and myself were mainly based (!). This is true, asGutherz 

 ('08) has shown, of the very form (Gryllus) of which Buchner is writing, the single 

 odd chromosome (monosome) of the male, recognizable by its peculiar form and 

 other characters, being represented in the female by two such chromosomes. 

 This is also in agreement with the results of other recent workers on the Orthoptera 

 including Wassilieff, Davis, Jordan and Morse. I can therefore find no meaning 

 in Buchner's statement unless the word "Monosom" be used to denote simply 

 a chromosome-nucleolus, when the passage becomes at least intelligible. But 

 such a restriction in the meaning of this word is not justified by its etymology, 

 by the original definition of its author (Montgomery, '06a, '066) nor by the facts; 

 and it does not seem to accord even with Buchner's own usage elsewhere in the 

 paper. That Buchner's statement is totally at variance with the facts when cor- 

 rectly stated is shown by the following summary of my results, quoted from one 

 of the papers in which Montgomery first defined the word "monosome." "When 

 there is a single monosome in the spermatogenesis (as in Protenor, Harmostes, 

 Anasa and Alydus) there are two in the ovogenesis so that the ovogonia possess 

 always an even number of chromosomes" ('066, p. 145, italics mine). 



But even if we admit that the "accessory body" of the female is a chromosome 

 and not only is there no proof of this but many reasons for doubting it what ad- 

 verse bearing would the fact have upon the "theory"? None as far as I can see, 

 unless this chromosome were proved to be univalent and without a synaptic mate 

 Were all this true,new and unintelligible complications would arise in regard to the 

 numerical relations of the diploid and haploid chromosome-groups in both sexes; 

 but it is not worth while to consider these puzzles since they lie in a region not of 

 observed fact but of pure phantasy. 



