Here's lyrics I harvested somewhere - the first part is from a Hal Leonard songbook, so it should be pretty close to the original
-Joe Offer-

MAIRZY DOATS by Milton Drake, Al Hoffman, and Jerry Livingston
Copyright © 1943 (Renewed) by Al Hoffman Songs

I know a ditty, nutty as a fruitcake,
Goofy as a goon and silly as a loon.
Some call it pretty, others call It crazy,
But they all sing this tune:
Mairzy doats and dozy doats,
And liddle lamzy divey,
A kiddley divey too,
Wouldn't you?
Well if the words sound queer,
And funny to your ear,
A little bit jumbled and jivey,
Sing, "Mares eat oats
And does eat oats,
And little lambs eat ivy!"
Oh! Mairzy doats and dozy doats,
And liddle lamzy divey,
A kiddley divey too,
Wouldn't you-oo-oo-hoo?
A kiddley divey too,
Wouldn't you?

….and some additional verses….

Whailzy deals and sealzy deals
And baby fishy doysters,
A squiddley doysters too,
Wouldn't you?
Well if the words sound queer,
And funny to your ear,
All of you girlsters and boysters,
Say, " Whales eat eels
And seals eat eels,
And baby fish eat oysters!"
Whales eat eels and seals eat eels
And baby fish eat oysters,
A squid will eat oysters too,
Wouldn't you?

A whale will eat oysters too,
A squid will eat oysters too,
A kid will eat ivy too,

Wouldn't you?

Cowzy day and goatzy day
And little pigzy donuts;
A kiddely donuts, too, wouldn't you?
(Repeat)
Now if the words sound queer,
And funny to your ear,
You think you're gonna go nuts,
Say cows eat hay, and goats eat hay,
And little pigs eat donuts.
(ETC.)

This kid would much rather eat a donut than ivy, or oysters, for that matter.

Speaking of centipedes:
A centipede was happy, quite, until a frog in fun,
Said, "Pray, which leg comes after which?"
This threw her mind in such a pitch
She lay distracted in a ditch,
Considering how to run.