A third class of nuts is the almond,[1960] which has an outer covering, similar to that of the walnut, but thinner, with a second coat in the shape of a shell. The kernel, however, is unlike that of the walnut, in respect of its broad, flat shape, its firmness, and the superior tastiness of its flavour. It is a matter of doubt whether this tree was in existence in Italy in the time of Cato; we find him speaking of Greek nuts,[1961] but there are some persons who think that these belong to the walnut class. He makes mention, also, of the hazel-nut, the calva,[1962] and the Prænestine[1963] nut, which last he praises beyond all others, and says[1964] that, put in pots, they may be kept fresh and green by burying them in the earth. At the present day, the almonds of Thasos and those of Alba are held in the highest esteem, as also two kinds that are grown at Tarentum, one with a thin,[1965] brittle shell, and the other with a harder[1966] one: these last are remarkably large, and of an oblong shape. There is the almond known as the “mollusca,”[1967] also, which breaks the shell of itself. There are some who would concede a highly honourable interpretation to the name given to the walnut, and say that “juglans” means the “glans,” or “acorn of Jove.” It is only very lately that I heard a man of consular rank declare, that he then had in his possession walnut-trees that bore two[1968] crops in the year. Of the pistachio, which belongs also to the nut class, we have already spoken[1969] in its appropriate place: Vitellius introduced this tree into Italy at the same time as the others that we mentioned;[1970] and Flaccus Pompeius, a Roman of Equestrian rank, who served with him, introduced it at the same period into Spain. CHAP. 25. (23.)—EIGHTEEN VARIETIES OF THE CHESNUT. We give the name of nut, too, to the chesnut,[1971] although it would seem more properly to belong to the acorn tribe. The chesnut has its armour of defence in a shell bristling with prickles like the hedge-hog, an envelope which in the acorn is only partially developed. It is really surprising, however, that Nature should have taken such pains thus to conceal an object of so little value. We sometimes find as many as three nuts beneath a single outer shell. The skin[1972] of the nut is limp and flexible: there is a membrane, too, which lies next to the body of the fruit, and which, both in this and in the walnut, spoils the flavour if not taken off. Chesnuts are the most pleasant eating when roasted:[1973] they are sometimes ground also, and are eaten by women when fasting for religious scruples,[1974] as bearing some resemblance to bread. It is from Sardes[1975] that the chesnut was first introduced, and hence it is that the Greeks have given it the name of the “Sardian acorn;” for the name “Dios balanon”[1976] was given at a later period, after it had been considerably improved by cultivation.