BREEDING HABITS OF AMPHIBIA 



41 



and remaining subnnerged nnost of the time. Its greatest activity is seizing food, which 

 it does rapidly. It is negative to light. It should be fed on alternate days strips of beef, 

 beef heart, liver, earthworms, Tubifex, small newts, tadpoles, Daphnia. 



It reaches sexual maturity in 2 years. Inguino-amplexus usually in July, thousands of 

 eggs being extruded but often not all fertilized. Egg measure 1. 5 mm. , with jelly it is 

 3. mm. Embryos hatch out in 37 hours and Siluroid type transparent tadpoles appear 

 on third day. The tadpoles feed on Chlamydomonas. Developmental temperature must 

 be at least 22°C. 



The adult female: South African 

 clawed toad Xenopus Taevis. 



(Photo by courtesy of Drs. Weisman 

 and Coates, from "The South 

 African Frog in Pregnancy and 

 Diagnosis." N.Y. Biologic 

 Research Foundation, 1944.) 



Dorsal view Ventral view 



Amplexus (coupling) in Xenopus laevis. 



(From Dr. H. A. Shapiro 1936: 

 Brit. Jour. Exp. Biol. 13:48) 



AMBLYSTOMA JEFFERSONIANUM , Jefferson's salamander. This salamander is found 

 in southeastern Canada and northeastern United States westward to Minnesota and south- 

 ward to Virginia. It prefers cold climate and the adults measure about 7 inches from tip 

 to tip. It is primarily nocturnal, burrowing in loose soil and leaf mold, under logs. It 

 is bluish black or dark brown in color with numerous bluish white flecks concentrated on 

 its sides. The swollen vent of the male protrudes noticeably and its tail is longer and 

 flatter than that of the female. 



Breeding occurs in early spring and the exact time is dictated by the temperature. The 

 site is any pond, permanent or temporary, and the eggs are layed singly at the rate of 

 about 4 per minute and are attached to each other and to a twig. Never more than 300 

 eggs are layed, and the four jelly capsules often take on a greenish color due to the 

 growth of a unicellular plant. Mating occurs just before laying, and incubation takes 

 about 6 weeks in nature and about 2 weeks at laboratory temperatures. The larval period 

 lasts from 56 to 125 days, depending upon whether the pond dries up, and at metamorpho- 

 sis the larva is about 1-7/8 inches long. Sexual maturity is achieved in about 21 months. 



