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NEW YORK STATE MUSEUM 



Carapace evenly rounded behind the frontal region ; rostrum 

 short and bifid at the tip ; body with spines ; legs of moderate length. 



Fig. 14 Libiniaemarginata (After Rathbun) 



L . e m a r g i n a t a may be distinguished from L . d u b i a by 

 the greater number of spines on the carapace and by the median 

 row, consisting in the former of nine, and in the latter of six spines. 



Fig. 15 Libinia du bia (After Rathbun) 



Both Species occur, the former the more commonly, walking over 

 the bottoms of the shallow bays among the eelgrass, and they extend 

 out into deeper water. They are frequently dredged on the oyster 

 beds, and sometimes appear in such numbers that operations have 

 to be suspended till the spiders, as the fishermen call them, have 

 passed over. 



