St. Ives Problem/Linguistic Note

Linguistic Note on St. Ives Problem
Prime.mover remembers this riddle as the first in his book of nursery rhymes which he had when he was somewhat younger.

In that edition, the cats, as documented here, each had $7$ kits.

The word is an archaic or poetic one for the more usual kittens, which can also be seen in some renditions of this riddle.

Some sources use the word kitts in order to reduce the possibility of the word being confused with the word kit meaning pack of useful tools and materials.