BREEDING HABITS OF AMPHIBIA 



45 



The belly surface is spotted white. The male body is smaller but its tail is longer than 

 that of the female. 



Mating occurs in late summer and autumn, 

 and breeding is in the spring in open bogs, 

 shaded woodland pools, or along quiet 

 streams. The nests are mere cavities in 

 decayed wood, grass or moss. About 30 

 eggs are layed and incubation takes from 

 6 to 8 weeks, depending upon the environ- 

 mental temperature. The aquatic larval 

 period is about 6 'weeks, and sexual ma- 

 turity is 22 years. 



PLETHODON CINEREUS , the red-backed 

 salamander. Rather widely distributed 

 throughout the United States, particularly 

 in the middle west, but not overly abun- 

 dant. There are five toes on the hind 

 limbs. It is never more than 4 inches in 

 length, is wholly terrestrial, and has two 

 phases; one with black and the other with 

 red back. The male snouts are swollen 

 and they are smaller than the females. 



Mating occurs in October and again in the 

 spring, with egg-laying in June and July. 

 The eggs are layed in caj/ities in well- 

 decayed logs or stumps and a single clus- 

 ter may contain only about 14 eggs. De- 

 velopment is very different from that of 

 other Amphibia. 



fe.l'^S^ 



Pl^^>^ 



Courtship of salamanders, a and b: Two-lined salamander, 

 c and d: Newt. e and f: Marbled salamander (spermatophore 

 between pair in f). a, b, e, and f after Noble and Brady; 

 c and d after Bishop. 



(Courtesy C. H. Pope 1944: Chicago Mus. Nat. Hist.) 



TRITURUS PYRRHOGASTER , the Japa- 

 nese fire-salamander. This form is very 

 common in Japan and is characterized by 

 a black warty skin and a bright red belly, 

 with scattered black spots. The size is 

 generally about 6 inches, the males being 

 a bit smaller and having large vents and 

 pointed tails. May be fed strips of fresh 

 liver which they will ingest from the water 

 without prompting. 



Since these forms are imported, they are used in the laboratory and may be caused to 

 ovulate by the injection of frog pituitary glands or extracts of mammalian pituitaries. 

 Generally the best procedure is to inject two female frog pituitaries on alternate days for 

 three injections, then place the female in water with Elodea on which she can lay the eggs. 

 Females in colonies may have spermatophores, but if this is not the case the males can 

 be induced to drop spermatophores by pituitary treatment. The eggs are generally layed 

 after the third injection and a good female will give as many as 80 eggs. The females 

 seem to retain their spermatophores for a long period and the eggs are inseminated as 

 they are layed. 



TRITURUS VIRIDESCENS , the common newt, formerly known as Diemcytylus viridescens. 

 These small vermillion spotted newts are found throughout the United States and southern 



