. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 104 FRANK R. LILLIE. folds formed simply by the process of twisting of the embryo. This distinction is of importance in interpreting the results of the experiments. Hirota (94) notices the secondary fold on the upper side and says : " It seems to owe its origin to the presence of the sero- amniotic connection. ... It is always on the right side of the connection, and is pushed on towards the left. There takes place no folding before the allantois appears, and the longitudinal ex- • FIG. 6. Section of the same em
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 104 FRANK R. LILLIE. folds formed simply by the process of twisting of the embryo. This distinction is of importance in interpreting the results of the experiments. Hirota (94) notices the secondary fold on the upper side and says : " It seems to owe its origin to the presence of the sero- amniotic connection. ... It is always on the right side of the connection, and is pushed on towards the left. There takes place no folding before the allantois appears, and the longitudinal ex- • FIG. 6. Section of the same embryo as the preceding, 10 sections (150^) in front of Fig. 5. The section passes through the place of fusion of the right and left folds. The secondary fold of the amnion is well shown on the right side. Letters as in Fig. 5- tent of the fold depends on the extent of the sero-amniotic con- ; " Its form and extent are ; " It is not clear what significance this fold ; "At both extremities of the sero-amniotic connection the amnion is also slightly folded longi- ; These secondary folds of the amnion are very transitory ex- cept in two regions : (i) Above the hind end of the heart (apex of ventricle) and continuing a short distance behind it ; (2) in the region immediately in front of the allantois, at 60-70 hours, thus in the neighborhood of the final closure of the amniotic folds. The former are of very constant occurrence and persist a long time (Fig. 3). The latter are relatively slight and inconstant. Hirota is thus mistaken in saying that these folds do not appear until the formation of the allantois. The secondary folds in the neighborhood of the heart are always on the upper (right) side; they first appear at the time. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
