I'm suddenly conscious that I've still got a pile of these to show. Just because it shows a certain humour I suspect, but don't know for sure, that the Manley Hopkins cover is by Stephen Russ. Pretty confident the Dryden isn't but it's a striking cover anyway.
Don't think I've ever mentioned it before but if you're at all interested in Penguin Books, particularly from a design or historical point of view then it would pay to sign up to the brilliant Penguin Collector's Society. It doesn't cost much and you get their periodical full of fascinating and often intimate details of Penguin history, access to the Society's other, more irregular but equally revealling publications and even opportunities to attend occasional events.