Correlation ID and Message ID in JMS

i checked message header of two messages coming from WMQ server and found that Correlation ID is same for two messages but Message ID are different, as shown below:

  JMSMessageID:    ID:414d5120514d44332020202020202020ece34b503d2d7428
  JMSTimestamp:    1347271147937
  JMSCorrelationID:ID:414d5120514d44332020202020202020ece34b5005e87120
 
 
   JMSMessageID:    ID:414d5120514d44332020202020202020ece34b50292d7428
  JMSTimestamp:    1347271144225
  JMSCorrelationID:ID:414d5120514d44332020202020202020ece34b5005e87120 (Same as above)

so it means both are seperate entity.