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ESSENTIALS OP ZOOLOGY 



the right. Two trachea were present, the right being rather nor- 

 mally developed while the left was rudimentary. The brain was 

 normal, but joining the medulla were two separate and complete 

 spinal cords, one passing to each back region. Most of the internal 

 organs ''favored" the right side, except the lungs, of which the 

 left was much more developed. 



Dr. F. L. Fitzpatrick reports upon the anatomy of a double pig 

 also. This freak had two tracheae leading to two sets of lungs. 

 The brain consisted of a three-lobed cerebrum, two cerebellums, 



Trunh from other heart — 

 R. subclavian- 



R. carotid 



L. carotid 



-L. subclavian 



Ductus 

 arteriosus 



Parietais- 



Dorsal 

 aorta 



Porietals 



Allantoic- 

 (lef t back) 



Renal 



-Utero -ovarian 



^ External ill ac 



-'"^^'^ Allantoic r left) 



Caudal 



Fig. 72. — Dorsal aortae and branches in embryo pig which had a single head and 



two bodies. (After Fitzpatrick.) 



and two medullas. There was a spinal cord in each of the two backs. 

 A third or median eye was present on a ventral stalk beneath the 

 third or transverse lobe of the cerebrum. Two pairs of kidneys, two 

 bladders, four ovaries, double sets of oviducts and uteri, as well as 

 a double cloaca, were present. There was a single but modified heart 

 and two aortas leaving it. Externally the animal had two sets of 

 limbs, two tails, two sets of mammae, two anal apertures, and two 

 urinogenital openings. 



