Can You Tell Me The Difference Between These Bulbs??(hps and mh) sept3/2012

hello i had two light bulbs bestowed upon me, what i know is, ones a hps and ones a mh (both 400 watt). if you could tell me which ones which.... pic#1 and pic #2 (hps / hm) would be much obliged.
 

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hey, this will be my first indoor grow. right now i got northen lights(pure strain,seed), LSD(clone), and T-9(clone). will make a grow journal and thread when it progresses a little. can't wait :)
 
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