Two subspecies, H. n. nebulosus and H. n. tokyoensis are studied on the chromosome number and karyotypic characters. The chromosome number is 56 in both subspecies. Except no. 10 chromosome pair, the karyotype of the two subspecies is identical with each other. The no. 10 chromosomes of H. n. nebulosus are acrocentric, while submetacentric in H. n. tokyoensis. This change may be due to pericentric inversion. H. n. tokyoensis from Atsumi shows the karyotype similar to that of H. n. nebulosus.
The fine vascular changes in the rabbit endometrium on the 7th day after coitus when the blastcysts begin to contact with the epithelium in the antimesometrial area was studied by means of the scanning electron microscopy of resin casts. The placental fold showed the vasculature with marked changes including swelled radial arteries and veins, while the ob-placental fold was in a poor vascular arrangement of vessels. The pen-placental fold showed a vascular arrangement nearly identical to that of the placental fold.
The presence of two kind of precipitins against blood group H substances from the human stomach and ovarian cyst was demonstrated in eel (Anguilla japonica) sera by immunodiffusion techniques in agar gel. One of them which forms the precipitation line to antigen side is the known anti-H precipitin containing anti-H agglutinin activity. The precipitating activity of the eel anti-H serum with H substance was inhibited by L-fucose and 2'fucosyllactose. The anti-H precipitin also reacts well with H substance from the hog stomach, but does not show clear precipitation lines with human secretor salivas and 1% solution of preparations of H substances from the small intestine, meconium and semen. Another precipitin which forms a precipitation line to the antiserum side in agar gel reacts well with H substances from human secretions and tissues. Because this precipitin reacted with water-soluble substances from human secretor, the antigen was named H(Se) and antibody anti-H(Se). The anti-H(Se) precipitin is not absorbed with group O red cells and the H and H(Se) activities of H substance against eel precipitins are decomposed by α-(1→2)-fucosidase.