. The alligator and its allies. Alligators. 198 The Alligator and Its Allies until long after hatching. In the genus Alligator the trachea is straight. More universal than this looped structure there is found another peculiar structure in the crocodilian trachea. It is a short vertical partition in the stem just before its divi- sion into the two branches. This partition is partly mem- branous and possesses one or more stiffening cartilaginous strands which are outgrowths of so many cartilaginous rings of the trachea. The number of the stiffening fibers varies in the different species. The num
. The alligator and its allies. Alligators. 198 The Alligator and Its Allies until long after hatching. In the genus Alligator the trachea is straight. More universal than this looped structure there is found another peculiar structure in the crocodilian trachea. It is a short vertical partition in the stem just before its divi- sion into the two branches. This partition is partly mem- branous and possesses one or more stiffening cartilaginous strands which are outgrowths of so many cartilaginous rings of the trachea. The number of the stiffening fibers varies in the different species. The number of the tracheal rings varies not only in the different species but also in different individuals of the same species. There are be- tween fifty and sixty in A. mississippiensis. According to Rathke the number of rings in the individual animal al- most certainly does not in- crease with age. The number of rings is smallest in the gavials and greatest in the crocodiles (genus Crocodilus). The number of rings in the two. FIG. 57. RESPIRATORY ORGANS. b, bronchus; e, cesophagus; g glottis; /, lung; /, tongue; tr 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 Reese, A. M. (Albert Moore), b. 1872. New York, London, G. P. Putnam's Sons
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Keywords: ., bookauthorreeseama, bookcentury1900, bookdecade1910, bookyear1915
