In addition to the equitable titles and interests already considered and the equitable remedies to be considered beginning with the next chapter, there remain a class of cases where equity courts take jurisdiction on account of the character or number of the parties. Under this general head are included:

(a) Suits by or against married women;

(b) Suits between husband and wife;

(c) Suits between partners;

(d) Cases where equity takes jurisdiction on account of the number or diverse interests of the parties interested.