. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 94 BENSLEY. [VOL. II. distal limb, the latter curving cephalad above the ventral pos- terior margin of the liver, before passing into the midgut. Four regions may now be distinguished ; a very short ante- rior region without glands, provided with a ciliated epithelium, a region with flask-shaped glands and ciliated epithelium, a third region with tubular or saccular glands and a mucige- nous epithelium, and finally, at the posterior end, a region in which no glands at all are to be discerned. The second and third regions gra
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 94 BENSLEY. [VOL. II. distal limb, the latter curving cephalad above the ventral pos- terior margin of the liver, before passing into the midgut. Four regions may now be distinguished ; a very short ante- rior region without glands, provided with a ciliated epithelium, a region with flask-shaped glands and ciliated epithelium, a third region with tubular or saccular glands and a mucige- nous epithelium, and finally, at the posterior end, a region in which no glands at all are to be discerned. The second and third regions gradually merge into one another, but the pos- terior non-glandular portion is sharply marked off and forms, in part at least, the future pyloric gland region. At this stage the two pulmonary diverticula open into a capacious pouch lying below the foregut, into the floor of which it opens. In longitudinal sections the first gland appears immediately behind this sac. Farther back more glands make their appearance, and at the point where the foregut begins to enlarge into the stomach, it is completely encircled by six or eight of these large flask-shaped glands. Farther back again the glands become less and less flask-shaped and take on a tubular or saccular character. One of these anterior glands is represented in Fig. 4 as seen after staining in haemalum, followed by neutral gentian. The shape of the cells in the body of the gland varies with the degree of dis- tention. There seems to be in these glands an accumulation of the secretion in the lumen distending it, for it is only by the application of a distending force from within that the extreme stretching of the cells, which may be commonly observed, could be produced. In many glands where this distention is great. FIG. -c-Ambiystoma larva ,4 the cells are quite flattened and spread mm . in length ; oesophageal gland. Apoch. 2 mm., comp. out over a great surface, reminding one strongly of the appearance in the mam- malian blasto
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
