CLASS AMPHIBIA 493 



In the male specimen the yellow or brown-colored cylindrical 

 testes are located one in either side of the dorsal part of the body 

 cavity and each suspended by a fold of the dorsal peritoneum, the 

 mesorchium. The vasa efferentia, which are tiny sperm tubules 

 about the size of very fine threads, and the spermatic blood vessels 

 are suspended in this mesentery. The vasa efferentia enter the 

 medial side of the kidney (except at its anterior) and deliver 

 spermatozoa to a longitudinal Bidder's canal just within. This 

 canal is connected with the medial ends of collecting tubules and 

 through them the spermatozoa reach the Wolffian duct, as does the 

 urine. The Wolffian duct carries them to the cloaca. When the 

 spermatozoa reach the cloaca and bladder they clump into bundles 

 called spermatopliores, and are stored until breeding time. A Wolffian 

 duct (mesonephric duct) which serves both for conveying urine as 

 well as spermatozoa is called a duct of Leydig. 



In the female the pair of ovaries can usually be recognized by the 

 presence of eggs of some stage of development in them. When fully 

 mature each ovary seems to be a large sac full of large yellow ma- 

 ture eggs about the size of small peas. In specimens with immature 

 ovaries the eggs may be about the size of pinheads. Each ovary is 

 suspended from the dorsal peritoneum by a mesentery, the meso- 

 varium. There is a prominent, coiled, white oviduct or Miillerian 

 tube in the body cavity at each side of the other organs whose an- 

 terior end is suspended in the anterior portion of the body cavity 

 and spreads into a wide membranous funnel called the ostium. The 

 mesentery which supports the oviduct is the jnesotuharium. When 

 the ova reach maturity inside the ovary they escape by a rupture 

 in its wall which frees them in the coelomic cavity. Due to the 

 shape of the body cavity and position of visceral organs these eggs 

 move to the anterior part of the cavity and the ciliated mouths of 

 the two ostia receive them one at a time in each. As these ova pass 

 down the MuUerian tube (duct) they are met by spermatozoa, fertil- 

 ization occurs, a mucous substance is added as a cover by the glands 

 in the oviduct. These fertilized cells in a pouchlike posterior part 

 of each oviduct which is called the uterus and after a few accumu- 

 late they are deposited by passing from the body by way of the 

 cloaca and anus. These zygotes (fertilized eggs) are deposited by 

 attachment to the under sides of rocks, logs, etc. in the water in 

 small clutches of from 25 to 90 individuals. The embryonic stages 

 are passed here and the larvae hatch out as tiny fishlike organisms. 



