1. The lunate sulcus is present in 69 Japanese brains among 90, in 101 hemispheres among 180; the percentage is 76.7 for individuals, 56.1 for hemispheres.
2. As for the side of the appearance of the lunate, the left side (25 among 90 individuals, 27.7%) is far more frequent than the right (12, 13.3%). Among 101 hemispheres with the lunate sulcus 57 are left (56.4%), 44 are right (43.5%) As for the sexual difference the lunate sulcus is present more frequent in the female brain (17 among 24 hemispheres, 70.8%).
3. The site of the lunate sulcus is on the same hight with the occipital pole (66.3%), when it deviates, it is more frequent lower (28.7 %) than higher (5.4%).
4. The form of the lunate sulcus is almost half circle in 50.4%(type I-V), the others (type VI-XI) are more flat or bent down, the chord of the arc runs almost always from up and medial to down lateral.
5. The greatest distance from the occipital pol to the lunate sulcus is 2.6-3.5cm long in total, it is longer (3.1-3.5cm) by the half circle form, shorter (2.6-3.0cm) by the flat form.
6. The depth of the lunate sulcus is pretty deep, it's length is 3.1-5.0cm.
7. The situations of the lunate sulcus is up and lateral to the outer part of the retrocalcarine sulcus, except this retrocalcarine the upper and lower occipital sulci are surrounded by the arc of the lunate. A part of the upper occipital may situate out of the arc, the lateral occipital comes always lateral and out of the lunate.
8. The retrocalcarine sulcus is present in 135 among 180 hemispheres, its prolongation to the lateral side is observed in 88 among 135. The lunate sulcus comes in 61 among these 88, the remaining 40 hemispheres with the lunate are without retrocalcarine.
9. As for the anastomosing sulcus with lunate the upper occipital is more frequent than the lower occipital. The number of the anastomose is one in 45.5% among lunate hemispheres. The site of the anastomose is at the middle part of the sulcus, less frequent at the lower end and scanty at the upper end.
10. The lunate sulcus is almost always accompanied by the prelunate, , the number of the latter is one, less frequently two. Except this prelunate there are 2 or 3 collateral short accompanying sulci.
11. The dimensions of the cuneus on the medial surface are inclined to be a little broader by the lunate specimens. The angles between the calcarine and parieto-occipital sulci oscilate between 70° and 89°. It seems that there is no correlative relation between this angle and lunate.
12. By the lunate specimens are the intraparietal sulci not straight and run nearer to the mantle rim. At their caudal end the medial branch of the transverse occipital sulcus is longer than the lateral.
13. When a circumscript elevation on the outer surface of the occipital lobe may be called as operculum, there are 126 examples among 180 hemispheres. In the 101 lunate specimens there are 55 distinct, 24 not so much distinct operculum, 79 in total.
14. The sulci which limit the operculum at the upper margin are almost always the transverse occipital, at the lateral margin are the lunate, and when the latter deficient the lateral occipital.
15. The lateral occipital sulcus is distinct in 168 among 180 hemispheres, and when the lunate is present it lies always medial to the lateral occipital and horizontal. The anastmosis with the lateral occipital comes to the temporalis medius frequently (62 among 180).
16. The upper and lower occipital sulci are less marked by the lunate brains.
