. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. STRUCTURE AND DEVELOPMENT OF EMBIA TEXANA. I 15 line membrane is comparatively tough and separates from the chorion in eggs kept in an alcoholic preservative. Unfortunately the youngest embryos were well advanced at the time of preservation, being in an elongate fully-segmented stage. As the embryo now extends over the whole of the de- finitive dorsal surface with its head directed posteriorly, it prob- ably attained this position by rotation, keeping at the surface of the egg as in the Termites and not plunging through the
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. STRUCTURE AND DEVELOPMENT OF EMBIA TEXANA. I 15 line membrane is comparatively tough and separates from the chorion in eggs kept in an alcoholic preservative. Unfortunately the youngest embryos were well advanced at the time of preservation, being in an elongate fully-segmented stage. As the embryo now extends over the whole of the de- finitive dorsal surface with its head directed posteriorly, it prob- ably attained this position by rotation, keeping at the surface of the egg as in the Termites and not plunging through the yolk as in the Orthoptera with elongate eggs. At this stage segmenta- tion is nearly complete, only the posterior end being confused. The antennas are short, borne by the rather large deutocerebrum which shows a flexure around the posterior pole. The mouth. FIG. 6. Three stages of the developing embryo, aw, amnion ; ant, antenna ; c/i, chorion ; do, dorsal organ; far, labrum; in, micropile ; md, mandible; vixl, .„ max- illce, mxp, palpus; ser, serosa, th^, 2, 3, legs ; zr. m, vitelline membrane. parts are large, single-jointed appendages, the labrum distinctly bipartite. The head segments are nearly as strongly marked as the thoracic. Of the limbs the first pair are slightly more ad- vanced than the others. Whether this is due to the antero- posterior direction of growth or to an acceleration of these im- portant appendages would be hard to decide. The pleuropodia are large, the remaining abdominal appendages are uniformly smaller and disappear on the fifth segment. Beyond this segment the abdomen curves into the yolk, while at the eighth segment there is a sudden outward flexure. The " tail-piece " thus formed is quite like the similar growth of Termes, etc. Sections of the. 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 r
Size: 2281px × 1095px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
