anyone well versed in Phaedo?

This is for school, I take it?

Any more context?

I can guess the general meaning - but.....

This may help?

http://www.google.com.au/search?hl=en&ie=UTF-8&oe=UTF-8&q=Clito+AND+socrates&btnG=Google+Search&meta=

Clearly, he means they owe a debt to Crito - but for what I cannot yet guess...

This link looks promising.

http://www.noetic.org/Ions%5Cpublications/r52denney.htm

Socrates was dying from poisoned hemlock. His dying request was to his friend, Crito, in which he asked Crito to repay a debt he owed Asclepius. Apparently the cock was the necessarily payment of the debt. I never saw this as symbolic but rather a straightforward request.