. Current herpetology. Reptiles; Herpetology. YOSHIZAKI ET AL.— SHELL MEMBRANE OF TURTLE EGG. Fig. 3. Transmission electron micrographs of inner shell membranes from the Chinese soft-shelled turtle eggs on day 6 of incubation. (A, B) The fibers of shell membranes (SM) consist of two components, the medulla (m) and cortex (c). In the outer portion of the membrane, the fibers fuse to each other via their cortex. (C, D) At the interface with the egg white (EW), the shell membrane is demarcated by a layer of dense material called the limiting membrane (LM). There are small canals which run perpend
. Current herpetology. Reptiles; Herpetology. YOSHIZAKI ET AL.— SHELL MEMBRANE OF TURTLE EGG. Fig. 3. Transmission electron micrographs of inner shell membranes from the Chinese soft-shelled turtle eggs on day 6 of incubation. (A, B) The fibers of shell membranes (SM) consist of two components, the medulla (m) and cortex (c). In the outer portion of the membrane, the fibers fuse to each other via their cortex. (C, D) At the interface with the egg white (EW), the shell membrane is demarcated by a layer of dense material called the limiting membrane (LM). There are small canals which run perpendicularly or obUquely to the plane of the membrane (arrows). constriction of the magnum-isthmus junction of the oviduct, makes the outermost surface of the egg white smooth, and determines the shape of the egg white mass. Thus, the limiting membrane subsequently produced at the isth- mus might be formed uniformly without any obstructions. In soft-shelled turtle eggs, no peri-albumen layer was observed between the egg white and limiting membrane (unpub- hshed), and the magnum-isthmus junction is apparently absent in the oviduct (Girling, 2002). Then the materials for the limiting membrane might be polymerized on an irregular egg white surface, and as a result, canal-like struc- tures may appear as a vestige of ciliary pro- cesses of the egg white. Turtle eggs are not turned during embryo- genesis, unlike avian eggs. Neither the thick- ness of the limiting membrane nor permeabil- ity of the shell membrane change, indicating an absence of machinery which affects the structure of the membranes. Hence, turtle eggs. 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 Nihon Hachu Ryoseirui Gakkai. Kyoto : The Herpetological Society of Japan
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Keywords: ., bookcollectionbiodi, booksubjectherpetology, booksubjectreptiles
