The St.Bees limerick by Gilbert is the last in my favorite book of limericks... "An Explosion of Limericks" by Vyvyan Holland, son of Oscar Wilde. The collection is literary rather than scatalogical or salacious, and often pokes good fun at itself as in the Gilbertian example or this one:

There was a young man of Japan, whose poetry never would scan.

He said, yes I know that this really is so,

But I always try to fit as many words into the last line as I possibly can