الفهرس 
ACKNOWLEDGEMENTSOnly 14 pages are availabe for public view
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Abstract
The upper beak extends in a hook like infront of the lower beak. It measures 53.80 mm long.
- SEM shows that the tip and the lateral sides of the upper beak are covered by numerous flakes of keratin. At the free tip of the beak, these keratinized flakes have irregular appearance which may be due to desquamation of the epithelium during manipulation of foods.
- The oral roof constitutes 87.73%, while the pharyngeal roof constitutes 12.27% of the oropharyngeal roof length. It is clear that the length of the oral roof is about 6.5 folds that of the pharyngeal roof.
- The rostral part of the palate is characterized by the presence of median palatine ridge, rostral and caudal lateral palatine ridges, narrow part of the choanal slit and three rows of palatine papillae. The position, direction and length of these rows as well as the number of papillae they contain are different.
- The median palatine ridge (30.72 mm) consists of two parts; rostral continued (18.10 mm) and caudal interrupted (12.62 mm). The interrupted part bears 2-3 projections, it continues caudally within the proximal end of the choanal slit as a median fold.
- SEM reveals that, at the level of the beginning of the caudal lateral palatine ridges, the median ridge is characterized by the presence of 4-5 transverse furrows.
- Between the lateral edge of the upper beak and the rostral as well as caudal lateral palatine ridges being the lateral palatine groove which is narrow rostrally and becomes deeper and wider caudally.
- The choanal slit measures 27.62 mm long. It constitutes 38.30 % of the length of the palate. Its narrow part constitutes about 55.87 % and wide part 44.13 % of the length of the choanal slit.
- The edges of the narrow part of the choanal slit is smooth rostrally but slightly thickened caudally due to the presence of 2-3 small papillae. The edge of the wide part is thickened due to the presence of 5-7 conical and wedge shaped papillae.
- SEM indicates the presence of median fold within the choana. It represents the direct continuation of the median palatine ridge. After a short distance this fold bifurcates into right and left folds.
- Several openings of the palatine salivary glands are demonstrated on the palate at the level of the choanal slit.
- The pharyngeal roof continues rostrally with the oral roof at the level located between the choanal and infundibular slits. It terminates caudally at the pharyngeoesophageal junction which is demarcated by a transverse row of caudally directed conical papillae.
- The infundibular slit measures 6.93 mm long and constitutes 68.34 % of the pharyngeal roof length. It continues rostrally with the choanal slit and caudally with a shallow groove till the level of the pharyngeoesophageal junction.
- According to SEM, a numerous different sized and shaped caudally directed pharyngeal papillae are distributed in the roof of the pharynx. Between these papillae numerous openings of the sphenopterygoid salivary glands are scattered.
- In the dermis of the upper beak, nerve bundles and sensory corpuscles are demonstrated.
- The epithelium of the oral roof at the level of the choanal slit is stratified squamous epithelium which transforms at the edge of the choanal slit into pseudostratified ciliated columnar epithelium that interrupted by intraepithelial mucous glands surrounded by lymphatic infiltration and nodules.
- The pharyngeal mucosa demonstrates pharyngeal folds, intraepithelial mucous glands and abundant lymphoid infiltration and lymphatic nodules, in addition to intraepithelial sensory corpuscles.
- Numerous Periodic Acid-Schiff (PAS)-positive compound tubular mucous maxillary, palatine and sphenopterygoid salivary glands are distributed in the mucosa of the oropharynx.