DESCRIPTION OF A NEW SPECIES OF FRESH-WATER 

 COPEPOD OF THE GENUS MORARIA FROM CANADA 



By Arthur Willey 



0/ the Department of Zoology, McGill University, Montreal, Canada 



Last year the writer briefly recorded the finding of an undescribed 

 species of Moraria, a genus of harpacticoid copepods new to the 

 American continent, in a Laurentian mountain spring. This wa& 

 early in August, 1925. Those obtained on that occasion were all 

 immature. On revisiting the spot, near the station of Weir, Prov- 

 ince of Quebec, a month later, hoping to find more fully developed 

 individuals, the spring had run dry. This year, in the month of 

 July, there was again no water there, but fortunately in other locali- 

 ties I have found the same species in the mature state, namely, near 

 Shawbridge and at three stations oft" the Arundel road. One of the 

 sources for the material was not a spring but a sphagnum bog in 

 which pitcher plants were growing very luxuriantly beside a mud 

 lake near Macdonald Lake. 



Giesbrecht (1892, p. 768) drew attention to the fact that the cala- 

 noid fauna of the warmer parts of the ocean exhibits a greater degree 

 of specific divergence than in the North Atlantic. The reverse is true 

 of fresh-water copepods, especially the harpacticoids, where the num- 

 ber of species increases from south to north, a fact which not only 

 suggests a northern origin for these forms but also points to their 

 Pleistocene derivation. In other words, the northern fresh-water 

 harpacticoids, as an ecologic group, are relict forms of the postglacial 

 fauna. A double interest is attached to them on this account. There 

 is another point that requires repeated confirmation. It was tenta- 

 tively assumed by the writer that the North American fresh-water 

 harpacticoids differ, to the extent of certain unit characters, from 

 their nearest representatives in the Old World. The present species 

 seems to bear out that interpretation. 



The genus Moraria, named after Loch Morar in Argyllshire, Scot- 

 land, was estabhshed in March, 1893, by T. and A. Scott. It super- 

 sedes the name OphiocamjJtus introduced by Mrazek in May of the 

 same year. Two of the principal species that have been described 



No. 2673.-PROCEEDINGS U. S. NATIONAL MUSEUM, VOL. 71, ART. I 



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