V.S. of Skin
- v.s. skin of pigeon shows main two layers: Epidermis, Dermis.
- Epidermis contains the following layers : (i) Outermost layer is called as epitrichium made up delicate cells, (ii) Below epitrichium is cornified layer called as stratum corneum. (iii) Beneath stratum corneum is stratum germinatum or stratum Malpighii consisting dividing cylindrical and uninucleated cells.
- Dermis is made up of following layers: (i) Vascular spongy layer just beneath stratum germinatum.
It has such blood supply, nerves, muscles, connective tissue, (ii) Below spongy layer is compact layer of fat.
- In the section dermal papilla for permanent feather, feather follicle, pulp, calamus of down feather with barbs are seen.
- Only gland present is preen gland or uropygal gland near tail
Identification: Since the section contains calamus and above features hence it is V.S. of skin of pigeon (bird).
L.S. of Crop
- Section shows outer covering made up elastic thin layer.
- Internally crop contains epithelial layer and crop glands.
- During reproduction the glands secrete delicate nutritive substance called pigeon milk. The pigeon milk is secreted by both sexes. Pigeon milk is fed to young pigeons by beak. It is regurgitated into the mouth by parent. until young on are able to feed on grains.
- The epithelial layer also contains mucus glands.
Identification : Since the section contains crop glands and above feature, hence it is L.S. of crop of pigeon.
V.L.S. of Proventriculus
- Part above gizzard is called is proventriculum. Section shows that proventriculus opens into gizzard by cardiac opening.
- Interior of proventriculum contains thick mucous glands which secretes gastric juice.
Identification : Since the section contains thick mucous gland and above features, hence it is V.L.S. of proventriculus of pigeon.
T.S. Passing Through Hand Cut Section of Gizzard
- Gizzard is highly thick and muscular. T.S. passing through gizzard shows that it is composed of serosa, tendinous layer, folded mucosa, longitudinal muscle layer and thick circular muscle layer.
- Lumen of gizzard is surrounded by thick rough, horny, yellow or green coloured epithelial linings which make gizzard very narrow.
- Horny lining contains pieces of stones which help in grinding of food.
Identification : Since the lumen contains horny lining and stones, hence it is T.S. of gizzard of pigeon.
Development of Down and Contour Feather
- At 5th or 6th day of incubation feather starts developing as primordium dermal feather papilla or pimple over the skin (A, B).
- Each papilla arises as group of cells beneath delicate and transparent epidermis the papilla rudimentarydown feather (C).
- Base of papilla sinks and forms feather follicle. From feather follicle it grows as feather germ (D).
- Base of feather germ lies in stratum germinatum which forms series of vertical radiating ridges which later on differentiate into rami or barbs lower part of feather forms thickened bare or quill (E, F).
- A transparent sheath originating from stratum germinatum encloses growing feather. The central soft mass forms the pulp which is nutritive zone for the feather (G. H).
- Later on barbules developed.
- As the feather grows, it is peald off and feather with barbs emerges.
- In case of contour feather fresh papilla is formed at a deeper level. In case of contour feather the ridges of Malpighian layer give rise to rachis or shaft containing barbs (I).
Identification: As the slide contains dermal papilla and above features, hence it in V.S. development of feather of pigeon.