"an ass or an ox or a lamb": This tells me only of these. Whence am I to derive all beasts (as included)? From all beasts to watch." For wherever the general adds to the particular, all are included. Then let only that (the general) be stated. Why need the others be specified? In that case I would say that he is not liable until he deposits all of them with him. It is, therefore, written "an ass or an ox or a lamb," to make him liable for each individually.