
Thank you Joshua and Jim--I got the tick marks on finally!
One last question: I am supposed to make bins in 1, 2 and 5 mm increments for fish up to 170 mm.  I assume these are the breaks?  So breaks = 170 for 1 mm and 340 for 2 mm and 1550 for 5 mm?  I couldn't find any specific examples in the R manual.  The problem is I don't think that is correct, as the histogram disappears at breaks = 1550.
Thank you again,
Julie 		 	   		  
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