Menahot 92: The Atonement of the Laying of Hands

On the requirement of "semicha" - the laying on of hands before slaughtering an animal, and how it's the subject of the first recorded debate in the Oral Law. Plus, the way the placing of hands is part of the process of offering the sacrifice, together with atonement. Also, which animals require that laying on of hands? It's not all of them - where a bull does require it, but the goats brought in atonement for idolatry, well, that's a machloket. And what is the province of the elders, as compared to Aharon/the kohen gadol?