GENERAL ZOOLOGY 



Antenna 

 Antennule 



Penis 



Developing eggs 



Fig. 15.9. Branchiopoda : the 

 fairy shrimp, Branchinecla paln- 

 dosa. A, male; /?, female. 

 (Redrawn, after A. S. Pack- 

 ard, from H. B. Ward and 

 G. C. Whipple, Freshwater 

 Biology, copyright 1918 by 

 John Wiley and Sons, Inc., 

 printed by permission.) 



distinguishable from females by their second antennae, which are grotesquely 

 modified as organs for clasping the female at the time of copulation. Fertilized 

 eggs are carried for a time in a brood pouch on the ventral surface of the 

 abdomen of the female. Alter these zygotes are released, they are very 

 resistant to freezing and desiccation and so remain viable after the temporary 

 ponds have dried up. These persistent zygotes produce the adults of the 

 following spring, hatching as free-swimming nauplius larvae with three pairs 

 of appendages and a single median eye. The adult arises from the nauplius 

 through a series of molts, in the course of which the characteristic features 



Fig. 15.10. Cirripedia. .4, an encrusting barnacle, 

 Balaam. B, a stalked or goose barnacle, Lepas. (Photo- 

 graphs by George Lower. ) 



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