scarcely distinguishable from the substance along which it moves, and scarcely seeming to move at all, until it has come within reach of its prey.  Then suddenly, with a motion rapid as that of the most agile bird, the long cylindrical and readily extensile tongue is darted forth with unerring aim, and the prey is seized and swallowed in a single moment of time.  The ordinary color of the chameleon is a pale olive-green.  This sometimes fades to a sort of ashen-gray, while sometimes it warms to a yellowish-brown, on which are seen faint spots of red.  Modern naturalists, for the most part, attribute the changes to the action of the lungs, which is itself affected chiefly by the emotions of anger, desire, and fear. [PLATE XXVIII., Fig. 5.]

The great extent of the Empire caused its vegetable productions to include almost all the forms known to the ancient world.  On the one hand, the more northern and more elevated regions bore pines, firs, larches, oaks, birch, beech, ash, ilex, and junipers, together with the shrubs and flowers of the cooler temperate regions; on the other hand, the southern tracts grew palms of various kinds, mangoes, tamarind-trees, lemons, oranges, jujubes, mimosas, and sensitive plants.  Between these extremes of tropical and cold-temperate products, the Empire embraced an almost infinite variety of trees, shrubs, and flowers.  The walnut and the Oriental plane grew to avast size in many places.  Poplars, willows, fig-mulberries, konars, cedars, cypresses, acacias, were common.  Bananas, egg-plants, locust-trees, banyans, terebinths, the gum-styrax, the gum-tragacanth, the assafoetida plant, the arbor vitse, the castor-oil plant, the Judas-tree, and other somewhat rare forms, sprang up side by side with the pomegranate, the oleander, the pistachio-nut, the myrtle, the bay, the laurel, the mulberry, the rhododendron, and the arbutus.  The Empire grew all the known sorts of grain, and almost all the known fruits.  Among its various productions of this class, it is only possible to select for notice a few which were especially remarkable either for their rarity or for their excellent quality.

The ancients celebrated the wheat of AEolis, the dates of Babylon, the citrons of Media, the Persian peach, the grapes of Carmania, the Hyrcanian fig, the plum of Damascus, the cherries of Pontus, the mulberries of Egypt and of Cyprus, the silphium of Gyrene, the wine of Helbon, the wild-grape of Syria.  It is not unlikely that to these might have been added as many other vegetable products of first-rate excellence, had the ancients possessed as good a knowledge of the countries included within the Empire as the moderns.  At present, the mulberries of Khiva, the apricots of Bokhara, the roses of Mexar, the quinces and melons of Isfahan, the grapes of Kasvin and Shii-az, the pears of Natunz, the dates of Dalaki, have a wide-spread reputation, which appears in most cases to be well deserved.  On the whole, it is certain that for variety and excellence the vegetable products of the Persian Empire will bear comparison with those of any other state or community that has as yet existed, either in the ancient or the modern world.