53 2 



COLLEGE ZOOLOGY 



side of the ventricle. This blood is pumped out through the 

 right aortic arch (ad), which merges into the dorsal aorta (d.ao). 

 Because the septum dividing the ventricle into two parts is 

 perforated, the blood that enters the right aortic arch is 



a mixture of purified blood 

 from the left auricle and 

 venous blood from the right 

 auricle. 



There is no renal portal 

 system in the turtle, but the 

 hepatic portal system shows an 

 advance in development over 

 the condition as described in 

 the frog (p. 489). 



The Respiratory System. — 

 Turtles breathe by means of 

 lungs. Air enters the mouth 

 cavity by way of the nasal 

 passages. The glottis opens 

 into the larynx, through which 

 the air passes into the trachea 

 or windpipe. The larynx is 

 supported by the hyaid ap- 

 Fig. 442. — Cloaca and urinogenital paratus. The trachea divides, 



organs of a turtle, Chelydra serpentina. .. » r. *„ „„„i, 



c,c>, blind sacs of cloaca; d, cloaca; sending one bronchus to each 



e, epididymis and vas deferens; p, penis, lung. The lungs are more 



HSS71& TZiJ; £,°do e ac°«° complicated than those of Ah- 



opening of bladder; v, bladder. (From pHIBIA. The bronchi branch 

 Sedgwick's Zoology, after Gegenbaur.) & ^^ q{ ^^ ^ ^ 



lung cavity is broken up into many spaces, thus increasing the 

 respiratory surface. 



The shell of the turtle prevents the expansion and contraction 

 of the lungs by means of abdominal or thoracic muscles. Air 

 is therefore drawn in and expelled partly by the hyoid apparatus 

 and partly by alternately extending and drawing in the neck 



