144 



THE ANATOMY OF VEKTEBRATED ANIMALS. 



and the pneumatic duct opens upon the ventral aspect of 

 the OBsophagiis. The air-bladder thus becomes exceedingly 

 like a lung; but its vessels are in communication with 

 those of the adjacent parts of the body- — not with the heart, 

 as in a tiTie lung. 



In Lepidosteus, the ducts of the male and female repro- 

 ductive organs are continuous with those bodies, and each 

 duct opens into the dilated ureter of its side. In the other 



Fig. 42. 



F\". 42. — The female reproductive organs of Amia calva:—a,a, the 

 open ends of the genital ducts ; b, b, oviducts; c, d, the right and 

 left divisions of the urinary bladder; e, e, the openings of the 

 ureters into the bladder;/, the anus; ff, ff, the abdominal pores : 

 li, the urogenital aperture. 



Ganoids the proximal ends of the genital ducts, in both sexes_ 

 open widely into the abdominal cavity. In Polypterus the 

 united ureters open into the cavity of the confluent ovi- 

 ducts, while, in the other Ganoids, the oviducts open into the 

 dilated ureters. (Fig. 42.) 



