(Mishnah): One who eats on Yom Kipur k'Koseves (the volume of a big date), like it and its pit, and one who drinks Melei Lugmav, is Chayav [Kares].

All foods join to k'Koseves, and all drinks join to Melei Lugmav. If he ate and drank, they do not join.

(Gemara - R. Yosah) Inference: One must squash the cavity (between the date and its pit). If you would not say so, it should teach "and like its pit and its cavity''!

(Beraisa - R. Shimon ben Elazar): This refers to a date of Beis Nimrah (in Ever ha'Yarden - Bamidbar 32:36. It is smaller than those of Eretz Yisrael - HA'GAON RAV C. KANIEVSKY, SHLITA.)