FISHERY BULLETIN; VOL. 72, NO. 3 



for variation were from collections in the National 

 Museum of Natural History (USNM), including 

 new collections acknowledged below. 



Measurements and counts used in assessing 

 variation were: 1) carapace length from rear edge 

 of orbit to posterolateral margin, 2) length and 

 width of antennal scale (ventral view), 3) lengths 

 of inner and outer uropods, 4) number of spines 

 in ventral comblike row on inner uropod near 

 distomesial margin of statocyst vesicle, 5) length 

 of this row of spines, 6) number of spines per 0.01 

 mm in this row, 7) number of spines on margin of 

 telson, and 8) relative widths of cornea and 

 eyestalk. External morphology of representative 

 specimens from over the range was studied and 

 compared. 



Specimens measured for comparisons were 

 mature adults (mainly females) from the follow- 

 ing collections: USNM 89736, St. Andrews, near 

 Atlantic Biological Station, N.B.; USNM 82658 

 and 82651, Woods Hole, Mass., received 2 January 

 1907, Vinal N. Edwards, collector; USNM 78734, 

 Amityville, Long Island, N.Y., 6 August 1938, 

 H. K. Townes, collector; USNM 143770, York 

 River below West Point, Va., 14 January, 1964, 

 W. A. Van Engel, collector; USNM 143771, Gar- 



bacon Shoal, 6 May 1964, W. C. Noe, collector, 

 and USNM 143772, Wilkinson Point, 17 June 

 1964, Frank Holland, collector, Neuse River, N.C.; 

 USNM 143773, Wassau Sound, Ga., 29 August 

 1972, and USNM 143774, mouth of St. Catherines 

 Sound, Ga., 30 January 1970, Richard W. Heard, 

 Jr., collector. All specimens were large winter 

 animals except the samples of summer animals 

 from Amityville, N.Y., and Wassau Sound, Ga. 



RESULTS AND DISCUSSION 



Morphological Analysis 



Proportional and meristic characters were 

 evaluated for variation in different parts of the 

 range. Mean carapace length in millimeters (rear 

 edge of orbit to posterolateral margin) for the 

 samples analyzed were: (Figure 1) New York, 

 2.95; (Figures 1, 2) New Brunswick, 3.03; Mas- 

 sachusetts, 3.25; Virginia, 3.51; North Carolina, 

 3.03; Georgia, St. Catherines Sound, 3.91 - Was- 

 sau Sound, 2.09; (Figure 3) New Brunswick, 3.01; 

 North Carolina, 2.74; Georgia, as above. There is 

 no detectable difference in size between males and 

 females of assumed comparable age. 



26 



24 



22 



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I 20 



3 



2 18 



o 

 ^6 



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12 - 



10 



8 - 



 • 



* * 



O * 



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 o o o o 



 ® 



* •  



*♦ ♦* • 



 ♦A ♦*  



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4 4 4M * Ok A a a 



A a ▲ a oD o 



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A = N.B. 

 a = MASS. 



* = N.Y. 



 = VA. 



 -N.C. 

 O^WASSAU SD.. GA. 



• =ST. CATHERINES SD., GA. 



I 



_1_ 



_L 



_L 



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2.0 2 .4 .6 .8 3.0 .2 .4 .6 .8 4.0 .2 



LENGTH CARAPACE (MM) REAR OF ORBIT TO POSTEROLATERAL MARGIN 



.6 



Figure 1. — Relation between number of spines in comblike row on inner uropod and length of carapace from rear 

 edge of orbit to posterolateral margin in seven populations of Neomysis americana. Framed points = replicates. 



836 



