

NATURAL HISTORY. 



'fairy-shrimp' often applied to it, for no fairy could excel it in shape, 



color, or delicacy. 



In some of the roadside pools formed by the melting snow these fairy- 

 shrimps occur in greai numbers. Visit the place a month later, and not 

 one can be found ; the pool itself has vanished, and its place is occupied by 

 the young grass. Yet the next year the pool will be there, as the snow 

 melts and in it will be the same beautiful forms. The question at once 

 arises, Where did they go and how did they return? The answer is a 

 simple one now that we know the life history of the form in question. 

 During their brief life they formed their eggs and dropped them on the 

 bottom, where they remained through the summer's heat, to reproduce the 

 species the next year. The parents died with the drying-up of the pool, 

 I ii it the eggs remained. A number of years ago a European naturalist 

 wished to study the growth of these or allied forms, so he obtained a num- 

 ber and placed them in an aquarium. They matured their eggs, dropped 

 them on the bottom, and then died. With the new year he expected to 

 obtain the young and to study them. All through the summer and fall 

 the water stood in the tank ; winter passed, and spring came, but not a 

 young fairy-shrimp was to be found. Another year passed, but brought no 

 better results. What was the matter? Had the eggs died? or were the 

 circu instances unfavorable ? You would never guess the true reason. The 

 - have to dry and then be moistened again before they will develop. 

 The summer's heat does not injure them, but, on the contrary, is an abso- 

 lute necessity. Since this fact was known, the study 

 of these forms lias become an easy task. All 

 that one needs to do, is to take some of the mud 

 from the bottom of one of the pools in which they 

 live, dry it, and*then put it in an aquarium, and the 

 young will hatch from the eggs in the earth, in 

 the greatest abundance. It was in this way that 

 Professor Siebold, in Germany, was able to study 

 forms from the interior of Africa, and Dr. Gissler, 

 in Brooklyn, the development of a species from 

 Kansas. 



These forms all pass through a metamorphosis 



in the course of their growth. From the egg 



there hatches out a curious larva, much like that 



which, as will readily be seen, bears not the 



to the adult. It has a single median jet-black 



eye, and hut three pairs of appendages. Larval forms like this are 



very ahunda.it in the sea, and have long been known. Years ago, be- 



Fig. 116.— Young (nauplius 

 stage) <>i the Eairy-shrimp 



"i Km-ope, enlarged. 



mow 



n m 



Figure 



11G. 





