|Calotes (Garden lizard)
|1. Paired external nostrils are small and oval apertures situated dorsally at the tip of the snout.
||1. Paired external nostrils are oblique slits present far above the mouth and lie at the base of the upperbeak.
||1. Paired external nostrils are oblique slits lying a little above the mouth.
|2. External nostrils are uncovered and are not connected to the mouth.
||2. Same as in calotes.
||2. External nostrils are partly covered by fleshy tip of the snout and are connected with a cleft in the upper lip.
|3. External nostrils possess valves.
||3. Valves are absent.
||3. Valves are absent.
|4. Nasal chambers are small and do not have the conchae.
||4. Nasal chambers are small and conchae are present.
||4. Nasal chambers are long and have conchae.
|5. Nasal chambers remain separate throughout as there are two internal nostrils.
||5. Nasal chambers remain separate throughout as these are two internal nostrils.
||5. Nasal chambers join posterior as there is a single internal nostril.
|6. Paired internal nostrils open into the anterior part of the buccal cavity.
||6. Paired internal nostrils open into the posterior part of the buccal cavity.
||6. Internal nostril opens into the pharynx.
|7. Glottis is without epiglottis.
||7. Same as in calotes.
||7. Glottis is covered by a cartilagenous plate-epiglottis.
|8. Larynx is supported by a pair of arytenoids and a median single cricoids cartilaginous plates.
||8. Larynx is supported by the same cartilagenous plates as in calotes. But the cricoid is sub-divided into four pieces procricoids.
||8. Larynx is supported by four cartilagenous plates. Median ventro-lateral Thyroid, ring-like lower cricoid and paired arytenoid cartilages on the dorsal side. It is also lined by ciliated epithelium.
|9. Laryrnx is a voice-box by possessing paired vocal cards which are functional.
||9. Larynx is poorly developed and nonfunctional, ie. The sound is not produced.
||9. Larynx possesses a pair of vocal cards and their vibrations produce sound.
|10. Larynx has two paired muscles - innermusculus compressor laryngis and outer musculus dilater laryngis. It opens into the trachea.
||10. Same as in calotes. Larynx opens into the trachea.
||10. Same as in Columba and the larynx opens into the trachea.
|11. Trachea is supported by complete cartilaginous rings.
||11. Trachea is supported by incomplete bony rings present dorsally.
||11. Trachea is long, thin walled tube, supported by incomplete cartilaginous rings present dorsally.
|12. Bronchi have complete cartilagenous rings.
||12. Median incomplete cartilagenous rings are present in the bronchi.
||12. Bronchi have incomplete median and dorsal cartilaginous rings.
|13. Bronchides are not formed.
||13. Bronchides are formed in a complex manner.
||13. Bronchides are formed by repeated branching of bronchi.
|14. Syrinx is absent.
||14. The sound producing organ Syrinx is present at the bifurcation of the trachea.
||14. Syrinx is absent.
|15. Lungs have orange colour. These are elongated bodies of fairly large size.
||15. Lungs have pinkish colour. These are ovoid organs relatively small in size.
||15. Lungs have pinkish colour. These are irregular organs of large size.
|16. Lungs are hollow sacs with thin elastic wall. These are having low septa and shallow alveoli on the inner surface.
||16. Lungs are compact spongy organs. They are slightly distensible.
||16. Lungs are soft, spongy and elastic organs.
|17. Lungs are not differentiated into lobes.
||17. Same as in calotes.
||17. Lungs are divisible into lobes. The right lung has four lobes Anterior azygos, anterior, posterior and posterior azygos. The left is divisible into two lobes-anterior & posterior.
|18. Lungs are enclosed by peritoneum.
||18. Lungs don't have peritoneum on the dorsal side.
||18. The lungs are completely covered by peritoneum. The space between the lungs is called mediastinum where heart is present.
|19. Air sacs are absent.
||19. Lungs are associated with thin, transparent air sacs. There are nine air sacs. These are, median interclavicle, paired cervical, paired anterior thorasic, paired posterior thorasic and paired abdominal air sacs.
||19. Air sacs are absent.
|20. The inter costal muscles help during the processes of inspiration and expiration.
||20. The inter costal and abdominal muscles help during the processes of inspiration and expiration.
||20. The inter costal muscles and peripheral muscles of diaphragm help during the processes of inspiration and expiration.
|21. Gaseous exchange occurs through the entire inner surface of the lungs.
||21. Gaseous exchange occurs in the blood capillaries present in the lungs. Double respiration takes place since the air is preserved in the air sacs.
||21. Gaseous exchange takes place in the alveoli present within the lungs.
|22. Some deoxygenated residual air is left over in the lungs. Hence aeration of blood is not very efficient.
||22. Residual air is not left over in the lungs.Hence aeration of blood is very efficient.
||22. Some deoxygenated residual air is always left over in the lungs. Hence aeration of blood is not so efficient.