Conn. Practice Book § 10-10

Supplemental pleadings showing matters arising since the original pleading may be filed in

actions for equitable relief by either party. In any

action for legal or equitable relief, any defendant

may file counterclaims against any plaintiff and

cross claims against any codefendant provided

that each such counterclaim and cross claim

arises out of the transaction or one of the transactions which is the subject of the plaintiff’s com -

plaint; and if necessary, additional parties may be

summoned in to answer any such counterclaim

or cross claim. A defendant may also file a counterclaim or cross claim under this section against

any other party to the action for the purpose of

establishing that party’s liability to the defendant

for all or part of the plaintiff’s claim against that

defendant.