. Elementary text-book of zoology. Zoology. FIG. 455.—Development of the embryo of HyilroplMug piceus (after Kowalevski). a, Shield- like ventral plate with raised edges. It, The edges are already growing together in the middle, c, The groove is almost entirely closed, d, The tail fold of the embryonic membranes has grown over the posterior end of the closed groove and is gradually extending forward; Am, Amnion. e, The embryonic membranes have almost entirely grown over the embryo, f, The embryonic rudiment beneath the completely closed mem- branes ; with seventeen primitive segments : El, Pro
. Elementary text-book of zoology. Zoology. FIG. 455.—Development of the embryo of HyilroplMug piceus (after Kowalevski). a, Shield- like ventral plate with raised edges. It, The edges are already growing together in the middle, c, The groove is almost entirely closed, d, The tail fold of the embryonic membranes has grown over the posterior end of the closed groove and is gradually extending forward; Am, Amnion. e, The embryonic membranes have almost entirely grown over the embryo, f, The embryonic rudiment beneath the completely closed mem- branes ; with seventeen primitive segments : El, Procephalic lobes; A, antennse. g, The ventral plate extends along the whole length of the ventral surface. The bi-lobed upper lip is present, also the antenna?, (A) the jaws, and the first rudiments of the legs; rudimentary appendages are present on the seventh segment as prominences. On the abdominal segments there are round invaginations, the first rudiments of trachese ; there is a longitudinal groove from mouth to anus. //, The ventral plate covers the whole ventral surface of the ovum ; the openings of the invagiuations (stigmata) have become small; rudimentary extremities are still present on the first abdominal segment. The ganglia of the ventral chain have appeared. !, Viewed from the dorsal surface the so-called dorsal plate has closed up to a tube; Oe is its opening. fr, The embryo just before- hatching seen from the ventral side. Hydrophilus these folds grow together over the ventral plate from behind forwards, and fuse with one another, so as to give rise to an. 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 resemble the original Claus, Carl, 1835-1899; Sedgwick, Adam, 1854-1913; Sinclair, F. G. (Frederick Granville), b. 1858. New York : Macmillan
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1884
