84 or Chauras!i I understand was a unit of measurement like we have the metric or the imperial system today. As we now measure metric units to 10,100,1000 and so on, but years ago the unit of measurement in the Punjab region was rounded of to 84. Hence 84 lakh or 84 man has also been used a example to measure weight. So the units are just an example of how vast the number of species there are. It's like saying that there are millions of life forms