ANIMAL STUDY 195 



Owing to their nocturnal habits they are seen by com- 

 paratively few people. They are easily secured, however, 



at this time of the year by raking out the 

 Salamanders . , 



leaves and other debris from ponds. These 



adults, after being kept a few days for examination, should 

 be returned to the ponds. The eggs are deposited singly 

 or in masses, enclosed in a jelly-like substance adhering to 

 twigs or to the stems of plants in the ponds. 



Secure the eggs as fresh as possible, place them in small 

 vessels, and note development. If secured very soon after 

 being deposited, the division of the egg can be seen with 

 the unaided eye. Later, note the formation of the spinal 

 groove in the embryo ; and still later, just before the young 

 are ready to hatch, note the budding and growth of the 

 external gills at the neck. Two or three days after hatch- 

 ing, the young salamander begins to feed. At first, it finds 

 food in the microscopic forms that are normally present in 

 the aquarium ; later, it feeds upon the water fleas and mos- 

 quito larvae ; and, still later, the tadpoles of frogs will sup- 

 ply its needs. In the absence of the latter it may be given 

 a small earthworm. If fed in this way it soon learns to 

 rise and take food from the hand when hungry. 



Note that the young salamander is fish-like at first, and 

 that the fore-legs appear soon after hatching as bud-like 

 growths just behind the gills. The hind legs appear much 

 later. A few days after hatching, the circulation of the 

 blood through the gills can be most beautifully seen under 

 the low power of the compound microscope. Place the 

 young salamander in a watch crystal of water and examine 

 the gills as transparent objects. Note that the blood in 

 such small amounts is not red, but a very light straw color. 



