The "kama-yari" (鎌槍, sickle spear) is essentially is a yari with horizontal kama (blade) at the base of the vertical blade to assist in hooking things.
The "kama-yari" (鎌槍, sickle spear) is similar to the jumonji yari. The kama-yari essentially is a yari with kama at the base of the blade to assist in hooking things.