Zoomorphology

Seifert, Gerhard; Rosenberg, Jörg

doi: 10.1007/BF00635998pmid: N/A

1. It is suggested that the eedysial gland ofLithobius forficatus formerly considered a strand of lymphatic tissue, be designated “glandula ecdysalis” in accordance with its function. 2. The gl. ecdysalis is a single-layered and irregularly folded epithelium surrounding the gl. mandibularis. It is bounded by its own basement membrane. 3. The cells of the gl. ecdysalis represent podocytes. Their pedicels rest on the basement membrane; the terminal ends are usually connected by diaphragms. Extending between the pedicels are widened intercellular clefts. 4. Along the intercellular clefts membrane vesiculations take place that give rise to coated vesicles. Associated specific tubular structures can transform into vacuoles. In the peripheral cell region only a few mitochondria and cytosomes are found. 5. The nucleus is located in the central cell region; it is surrounded by many golgi complexes. Only in the vicinity of the nucleus is a sparsely developed granular endoplasmic reticulum to be found. 6. With advancing postembryonic development the number of cytosomes increases; some become larger than the nucleus. 7. The moulting cycle is accompanied by changes of fine structure. After the critical phase, single lipid droplets and numerous accumulations of glycogen appear. Golgi complexes, mitochondria, and cytosomes seem to increase in number. 8. After ecdysis, and before the next critical phase sets in, neither lipid droplets nor glycogen can be found. Numerous cells disintegrate, and within the surviving ones vacuoles of varying size appear. 9. The organelles and structures described and their possible functions are compared with similar structures known from the literature.

Houtermans, Barbara; Schumacher, Rolf

doi: 10.1007/BF00635999pmid: N/A

The atympanal scolopal organs, located in the middle and back tibiae ofTettigonia viridissima L. have been investigated morphologically and were compared with the tympanal organs of the front legs. The results show that there are scolopal organs in these tibiae, too, which lack tympanic membranes; they consist of the subgenual organ, the intermedial organ and the crista acustica. The comparative investigation showed agreement in the following items: 1. In the middle and back pairs of extremities there are no symptoms for a beginning tympanisation. 2. The subgenual organs of all three pairs of extremities are almost equally developed, an indication for the independent functioning of the tympanisation. 3. The amount of the scolopidia of the intermedial organs as well as those of the cristae acusticae decreases from the front to the middle to the back leg. 4. The species-specificity which Schumacher (1973 a, b) has described concerning to the amount of the crista-scolopidia of the front tympanal organs, is not only relevant for the cristae acusticae of all three pairs of extremities, but also for the amount of the scolopidia of the intermedial organs.

Arni, Peter

doi: 10.1007/BF00636000pmid: N/A

The different cell types of the young postgastrulate embryo ofLymnaea stagnalis L. were studied by light- and electron-microscopy. Vacuoles containing perivitelline fluid were observed in all cell types of the ecto- and entoderm, but not in mesodermal cells. In the region of the midgut, cells with large vacuoles store the extraembryonic nutriment. They take up the perivitelline fluid from the gastric lumen by means of macropinocytosis. Micropinocytosis also occurs, just as in the other entodermal and most of the ectodermal cells. With the PJS-reaction and the treatment with ferritin we can demonstrat that various cells of the embryo contain galactogen—a constituent of the perivitelline fluid-in the cytoplasm apart from the vacuoles. The differing content of extraembryonic nutriment in the various kinds of cells is thought to be connected with their different performances. The electron-microscopic demonstration of acid phosphatase activity indicated digestive processes in the embryo. In all cells many yolk granules were observed. Most of them seemed to be involved in the cell metabolism. In part of the granules phosphatase activity occurred. The perivitelline fluid is the main nutrient reserve for the embryo. The yolk granules are subordinated with regard to the quantitative aspect of embryonic nutrition.