what does this mean? (letter from the professor)

[layla0302]

For Chem *** (Undergrad chemistry research for Juniors) my CRN for course registration is ******. You should register for 1/3 as many hours as you plan to work in the lab.


I can't understand what the professor is saying. I am starting to undergraduate research in his laboratory and I asked him about the registration for that research. And he gave me the answer like above. Could you please help on this?

[whitemoon]

What I understand is:
Suppose that you plan to work in the lab for 9 hours.
He suggests you should register for 3 hours (1/3).