Anatomy of the avian membrana nictitans
The anatomy of the membrana nictitans was examined in the rockhopper penguin (Eudyptes crestatus) and in two ducks, a diver (Mergus cucullatus, hooded merganser) and a nondiver (Anas platyrhynchos, common mallard), by light and transmission electron microscopy. In general, the nictitans is organized...
| Published in: | Canadian Journal of Zoology |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Canadian Science Publishing
1986
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/z86-146 http://www.nrcresearchpress.com/doi/pdf/10.1139/z86-146 |
| Summary: | The anatomy of the membrana nictitans was examined in the rockhopper penguin (Eudyptes crestatus) and in two ducks, a diver (Mergus cucullatus, hooded merganser) and a nondiver (Anas platyrhynchos, common mallard), by light and transmission electron microscopy. In general, the nictitans is organized in a manner reminiscent of the cornea; i.e., an external epithelium, an internal endothelium, and a fibrous stromal layer in between. However, it is thinner than the cornea, a fact reflected by the relatively thin stroma. Nictitans organization varies between species and in different regions of the same membrane. The cellular and acellular components are less organized and not as tighltly packed in the nondiver than in the two other species. In addition, portions of the nictitans that would be coincident with the cornea when it is in place in front of the eye are more highly organized in both divers. The anatomy of the leading edge of the nictitans, including the marginal plait, which may help lock the membrane in position, is described. |
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