Our Mishnah discusses the types of seals that were used in the Temple. We already mentioned these seals in the first Mishnah of the chapter: they were vouchers that a person would purchase for the nesachim - the fine flour, wine and oil that had to be brought along with the offerings. Four such vouchers were sold in the Temple.
"Arba chosamos hayu ba'Mikdash v'chasuv aleihen" - There were four seals in the Temple, and written on them were:
"Egel" - literally a calf, but this refers to any animal of the cattle family brought as an offering, since they all have the same measure of nesachim: three tenths of an ephah of fine flour, half a hin of oil and half a hin of wine.
"Zachar" - that is, a ram, whose nesachim are two tenths of an ephah of fine flour, a third of a hin of oil and a third of a hin of wine.
"Gedi" - a young lamb or a young goat. A male is considered a gedi as long as it has not passed its first year, and in practice up to thirteen months, and from then on its law is that of a ram. The nesachim of a gedi are one tenth of an ephah of fine flour, a quarter of a hin of oil and a quarter of a hin of wine.
"Chotei" - literally a person who sinned, and this is a veiled reference to the metzora. Once a metzora is purified from his tzara'as he is obligated to bring offerings, and if he is not considered poor he brings two male lambs and one female lamb. Each of them requires one tenth of an ephah of fine flour, a quarter of a hin of oil and a quarter of a hin of wine, and in addition he must bring one log of oil, which is used separately in the process of his purification. Because of that additional log, it was not possible to simply use three "gedi" seals, which is the third category, and therefore a separate seal was designated - a special voucher for the metzora that includes the separate oil.
The opinion of Ben Azzai:
Ben Azzai says "chamishah hayu" - there were five. And since the spoken language was Aramaic, the seals were written in Aramaic. The five were: egel - any animal from the cattle family; zachar - a ram; gedi - a young lamb or a goat; and two seals for the metzora: "chotei dal" - a poor sinner, and "chotei ashir" - a wealthy sinner.
The wealthy metzora is the one who brings the offering we mentioned - two male lambs and one female lamb, along with a log of oil. The poor metzora brings the same, except that in place of the two lambs he brings two birds, and birds have no nesachim at all. It turns out that all he needs is the wine, oil and fine flour that come with a single lamb, along with the log of oil. In Ben Azzai's opinion, a separate voucher was designated for this need as well.
The first Tanna, however, held that no separate voucher was needed for the poor man. For the wealthy metzora, who brings three lambs, a separate seal was designated; but the poor man does not need it, since the nesachim of a single lamb suffice for him, and that is all he has, along with one log of oil which he can bring from his own home.
The use of each seal:
"Egel meshamesh im niskei bakar" - the "egel" seal serves for the nesachim of cattle, large and small, males and females, all in a single measure.
"Gedi" - serves for the nesachim of the flock, whether mature animals or those within their first year, males and females, excluding males that have passed thirteen months, which are called rams and whose nesachim are a separate measure.
"Zachar" - serves only for the nesachim of rams, whose quantity of nesachim is separate.
"Chotei" - serves for the three animals of the metzora: the two male lambs and the female lamb, and in addition also for the log of oil, and this includes the asham offering.
In summary: In this Mishnah we learned about the four seals that were in the Temple - egel, zachar, gedi and chotei - each of which served for a different measure of nesachim: the nesachim of cattle, the nesachim of rams, the nesachim of the smaller flock animals, and the nesachim of the metzora's three animals along with the log of oil. We also examined the opinion of Ben Azzai, who counted five seals and distinguished between "chotei dal" and "chotei ashir", and the reasoning of the first Tanna, who saw no need for a separate seal for the poor metzora.