抄録
1. Chrom-osmic or chrom-osmic-bichromate mixture is recom-mended for the preservation of the chromosomes of the racoon dog as well as those of other animals.
2. Two kinds of spermatogonia, the spermatocyte in the early stage and SERTOLI's cell are found on the basement membrane of the seminal tubule of the racoon dog.
3. Forty-two chromosomes are found in the diploid set and twenty-one in the haploid including X and Y, of which thirteen pairs are atelomitic and eight pairs telomitic. The first division is reductional and the second equational in regard to the tangential rings. In regard to the other tetrads it remains undetermined which division is re-ductional.
4. The behavior of sex-chromosomes known as heteropycnosis seems to be due to the special colloid-chemical state of the matrix, and probably not to the lack of a homologous partner. MOHR'S hypothesis based upon the orthopteran sex-chromosome can not be applied in the case of vertebrates.
5. The chromosome formulae of the racoon dog as determined are as follows:
40+X+Y=42 spermatogonium
20+XY=21 1st spermatocyte
20+X=21 2nd spermatocyte a
20+Y=21 2nd spermatocyte b.
9. There is found in the racoon dog no chromosomal evidence to determine its genetical relation to the domestic dog, though the two animals resemble each other in their external and osteological charac-teristics, and also in the histological aspect of the testis.
