Moong Beans - Lentils - Mung Beans ?

The above image is of "Moong Beans."  But, the very same product I purchased at our local Indian Grocery Store a month or so ago called them "Green Lentils"  I made a wonderful Curried Dal with them. 

Now, I have used lentils in a large variety of dishes I have made for my wife and my family.... and when I first bought the "Green Lentils" I thought they were odd... but was assuming because they were not split like most available lentils, that explained the difference. 

But, although I am not sure, because my Internet searching has proven inconclusive and sometimes contradictory.... I am not 100% sure if lentils and moong beans are indeed the same or if they are actually two different items.  

Irregardless.... they seem to work similarly in recipies that call for lentils...... and I really enjoy traditional lentils and what is sometimes packaged as moong beans. 

To add to this confusion.... some sources on the Internet say moong beans are the same as mung beans.  But that confuses me even more.... because I use mung beans in one lab experience for students in one of my classes, and what I have that are called mung beans are BIG.... about the size of a kidney bean.  The moong beans / lentils are roughly the size of 1/4 inch or smaller (about 5 mm or so). 

So, if anyone has any more definitive information, please let me know.

PipeTobacco