I don't really see how a hippo looks much like a horse. Maybe a horse with a weight disorder, I guess. . .

Is anyone able to cite me to a humorous poem I partly recall, the plaint of a young lad bemoaning the loss of his beloved pet hippopotamus?

The lines I recall are that the lad nursed had his pet through "his hippopotameasles and his hippopotamumps," and that, "No longer in the morning will the neighborhood rejoice / To his hippopotamusically modulated voice."

Thanks in advance.