102 



U.S. NATIONAL MUSEUM BULLETIN 2 78 



nese waters (approximately 20° of latitude) whereas only 26 species are 

 found in the western North Atlantic (approximately 50° of latitude). 

 This paucity of species in the North Atlantic was observed by Mills 

 (1965) for the gammaridean genus Ampelisca. He stated that inter- 

 tidal species may be few because of winter ice scouring and that 

 perhaps sharp temperature zonation and a wide range of temperatures 

 do not favor the differentiation of stenothermal species. Many of the 

 caprellid species in the temperate zone of the western North Atlantic 

 are almost cosmopolitan in their distribution and appear to be highly 

 elastic eurythermal and euryhaline species. For example, CapreUa 

 penantis is found in most parts of the Atlantic and Pacific from the 

 boreal to the tropical zone and in salinities ranging from full sea water 

 to as low as 10 °/oo. 



Table 3 summarizes the known distribution of the caprellids of the 

 western North Atlantic (figs. 50-55). In general they correspond to 



Figure 50. — Distribution records of Hemiaegina minuta, Hemiproto zvigleyi, Mayerella 

 limicola, Mayerella redunca, and Metaprotella hummelincki in the western North Atlantic. 



