Chulin 3:7-4:1

Chulin 3:7

Kosher locusts are those that have four legs, four wings, legs for jumping, and whose wings cover the majority of their bodies. Rabbi Yosi says it must also be referred to as a locust. Kosher fish are those that have fins and scales; Rabbi Yehuda says that they must have at least two scales and one fin (because the former is plural in the Torah while the latter is singular). The Hebrew word "kaskeses" refers to the scales, which are attached to the fish; “snapir” refers to the fins, which a fish uses to swim.

Chulin 4:1

Let’s say that an animal was experiencing a hard labor; the fetus sticks out a leg and then pulls it back in. In such a case, if the mother is slaughtered, the calf may be eaten. If the calf stuck its head out, it is considered born even if it pulls its head back in (and therefore may not be eaten based on the slaughter of its mother). Anything that was separated from the fetus in the womb may be eaten but if it was separated from the mother’s spleen or the kidneys, it may not be eaten (because of the prohibition of eiver min hachai – not to eat a limb severed from a live animal). The general principle is that whatever is separated from the mother’s body is prohibited but whatever is not separated from the mother’s body is permitted.