326 



265 Fig. 131. Hyperia medusarum (O.Miiller). 



Dotted portion — shape of medusarum; rest — shape of hystrix (after Bowman, 1973). 



are smaller and exhibit morphological differences which led Bovallius 

 (1889) to describe them as a separate species, H. hystrix. Stephensen 

 (1924) studied the syntypes of Bovallius and treated H. hystrix as a 

 synonym of H. medusarum. bowman (1973) analysed vast material 

 and found specimens incorporating characters of both forms, which 

 compelled him to support the opinion of Stephensen. Living in notal 

 waters, H. gaudichaudi M.-Edw. is morphologically identical to the 

 northern H. medusarum f. hystrix and recognition of its specific separate 

 identity can only be based on its scattered area of distribution. 



Distribution: A bipolar species. Cold-water and moderately cold- 

 water regions for both Hemispheres. It is more oceanic than H. galba 

 and is absent in the Baltic Sea. In the Atlantic Ocean it is hot found 

 farther south than the North Sea, but in the Pacific Ocean along the 

 American coast is common up to 30° N. In the Southern Hemisphere 



