Those are hand made marbles called "swirls" and the ends are called pontils, not sprue stubs. They were twisted off a rod, not cast like a bullet with a sprue. Looks like you have three solid core swirls and a split core swirl on the right. Very nice marbles, and they are from the middle 1800s to about the 1920s. The "cats eye" marbles are nowhere as complex and were first made in the 1950s.
Gunsil is right. German handmade marbles! Nice old ones. That is called a pontil for lack of a better term because it's not a true pontil in the glassblowing sense, but they were rounded by hand and cut from a cane of glass one at a time.