Large POP inbox memory exhausted

[João Cortes]

I am trying to configure gnus to fetch my outlook account, via POP.
The inbox has ~3Gb. 
Gnus starts the fetching process but throws an error,

error in process filter: Memory exhausted--use C-x s then exit and restart 
Emacs [218 times]

Can I instruct gnus to fetch only a number of articles each time?
Is there any general rules regarding the size of newsgroups that gnus can 
manage?

My configuration

(setq gnus-select-method '
      (nnmaildir
       "MyMail"
       (directory "~/mymail/.nnmaildir") 
         (create-directory "~/mymail/maildirs")
       (get-new-mail t)))

(setq mail-sources  '(
                       (pop
                        :server "pop.gmail.com"
                        :user "mememe@gmail.com"
                        :port 995
                        :leave t
                        )
                       ))


Thanks