Electron microscopy of embryonic envelope formation by the cestode proteocephalus longicollis (zeder, 1800)(proteocephalidea)
1978 ◽
Vol 36
(2)
◽
pp. 444-445
Keyword(s):
Four main embryonic envelopes, the capsule, outer envelope, inner envelope and oncospheral membrane, are formed around the developing embryos of Proteocephalus longicollis, a parasite of fishes.The capsule, formed from shell-globule material of vitelline cells, is the first embryonic envelope which encloses the fertilized oocyte and a single vitelline cell (Fig. 1) when they pass through the ootype and enter the uterus. At this initial stage of embryogenesis, the capsule is formed of two closely apposed membranes (Fig. 1, inset). In more advanced stages, the capsule slightly increases its volume, and a fine-fibrillar material accumulates in the space between its two limiting membranes (Fig. 2).
1990 ◽
Vol 48
(4)
◽
pp. 798-799
Keyword(s):
2009 ◽
Vol 24
(8)
◽
pp. 2596-2604
◽
2007 ◽
Vol 24
(2)
◽
pp. 436-441
◽
Keyword(s):