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THE AMEBIC AN NATURALIST [Vol. XLIV 



With good feeding budding gives place to a sexual phase. On 

 the basis of daily observations of many cultures for a number of 

 years Nussbaum concludes that a more favorable nutritive con- 

 dition produces the female polyp. "The mass of food governs 

 budding and the production of sexual organs" — and the best 

 nutrition produces females. The same polyp may enter upon 

 repeated sexual phases each separated by a period of budding; 

 but, while he seems to deem it possible, he has not yet succeeded 

 in changing the sex of the same individual polyp directly into 

 the opposite sex. 



Here again the same general conclusion appears that sex is 

 consequent upon the degree of nutrition and that the best 

 nourished polyp produces eggs, i. e., high nutrition conditions 

 the female sex. 



Nussbaum suggests an interesting new interpretation of her- 

 maphroditism (gynandromorphism) among insects where a 

 dimorphism of spermatozoa prevails, e., where heterochromo- 

 somes are found. He believes it quite possible that occasionally 

 the reducing division may be omitted in spermatogenesis and 

 that the unmatured spermatocytes may develop directly into 

 functional sperm. Shortly before, or at the time of, the first 

 segmentation of an egg fertilized by such a spermatozoon, the 

 male pronucleus is supposed to undergo its belated reduction 

 division, one half (with the even number of chromosomes) pass- 

 ing to one daughter cell with one half of the developing egg 

 pronucleus, and the other half (with the odd number of chromo- 

 somes) with the other similar half to the other cell. Thus would 

 result a two-cell stage, one blastomere (female) containing one 

 more chromosome than the other blastomere (male). If then, as 

 has been experimentally demonstrated in several forms, each 

 blastomere gives rise to one half of the resulting individual the 

 symmetry of the insect hermaphrodite would be explained. Here 

 again sex is thought of as determined by a quantitative relation 

 of chromatin. 



The results of the newer investigations on sex-determination 

 seem, at least temporarily, to have brought us back to the posi- 

 tion of Geddes and Thomson, namely, that femaleness is caus- 

 ally related to a dominating cell-anabolism and maleness to a 

 relatively preponderant cell-katabolism. This conclusion would 

 seem to be the base from which future investigations will start 

 in the attempt to further elucidate the fundamental mechanism 

 of sex-differentiation. H. E. Jordan. 



