vitellarium


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vitellarium

[‚vid·əl′ar·ē·əm]
(invertebrate zoology)
The part of the ovary in certain rotifers and flatworms that produces nutritive cells filled with yolk. Also known as yolk larva.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Follicles were observed to develop gradually into the vitellarium, where the least mature follicles were located distally whereas the mature ones occurred proximally, close to the common oviduct (Fig.
(A) Female reproductive system of Scyphophorus acupunctatus formed by 2 ovaries (ov), germarium (g), vitellarium (v), oocyte (o), lateral oviduct (lo), common oviduct (co), spermatheca (s), and genital chamber (gc); (B) Distal part of the germarium (g) with bulky appearance possibly with trophocytes, prefollicular cells, and oogonia, terminal filament (tf), trachea (tr), tracheoles (trl); and (C) Approach to the onset of vitellarium with oocytes in development, germinal vesicle (gv), interfollicular tissue (tif), trachea (tr), and tracheoles (trl).
Immature eggs recorded in our enumeration are large individual egg chambers (follicle) located in the vitellarium whose oocyte displayed an ovoid form and had a slender tapering stalk at their posterior end in solid black color, and mature eggs recorded are large individual egg chambers (egg) of ovoid form that had a slender tapering stalk at their posterior end in black striped color.
Follicles are in increasing development stages along the vitellarium (from A to B).
Other identifiable structures included the vitellarium, suckers, gonads, ova, and intestine.
Parenchymal staining was less intense for NS than the PAS stain, though the vitellarium stained intensely with NS.
Ovary trilobed, sometimes round; situated to right of body midline in three specimens, to left in five specimens, between vitellarium and testes.
Remarks: According to Boomker (1984) and Brooks and MacDonald (1986), species in the genus can mainly be distinguished from each other by the position of the ovary relative to the vitellarium, i.e.
At no time during the observations in Repetec did we observe the formation of a brood ball, and this coincides with the state of the ovary in the females we dissected: in the vitellarium there were no mature oocytes, or only oocytes that were beginning to mature.
The ovarian follicles present in the vitellarium are divided into two interconnected chambers, the oocytic chamber that contains the oocyte and is located proximally to the nurse chamber that contains the trophocytes or nurse cells.
Photomicrographs of the female reproductive system of Megamelus scutellaris showing a) distal portion of the ovary showing the distal lateral oviduct (lop), common oviduct (co), bursa copulatrix (b), and spermatheca/spermathecal gland (spt and sptg, respectively), and b) close-up of ovariole morphology (b) showing the anterior lateral oviduct (loa), germarium (g), vitellarium (v), and terminal filament (tf).
The germarium presumably continued to produce eggs that underwent some development in the vitellarium before resorption, as the maximum follicle size did not decrease with time.