"Thy wit is as quick as the greyhound's mouth; it catches."
The greyhound alone among dogs can seize its prey while in full career.
In As You Like It (i. 2) Celia says—
"Here comes Monsieur Le Beau.
Rosalind. With his mouth full of news.
Celia. Which he will put on us as pigeons feed their young."
Pigeons have a way, peculiar to themselves, of passing food down the throats of their young.
In Twelfth Night (iii. I) the Clown says to Viola—
"Fools are as like husbands, as pilchards are to herrings,—the
husband's the bigger."
The pilchard is a fish of the herring family, which is caught in the Channel; it is longer and has larger scales.
In the same play (ii. 5) Maria says of Malvolio—
"Here comes the trout that must be caught with tickling."