144 p y T P Y X to have been the limit of his voyage in this direction. It must be observed also that amber is found on the western coasts of Germany, as well as in the Baltic, though not in equal abundance. It is a very singular fact that no mention is found in any ancient writer, in connexion with the voyage of Pytheas, of the Cassiterides or Tin Islands, the exploration of which might naturally have been supposed to have been one of the chief objects of his voyage. It is indeed not im- possible that the statements on this subject preserved to us from Timseus, who wrote less than a century after him, were derived from Pytheas, though there is no proof of this. The trade with those islands was probably at this period exclusively in the hands of the Phoenicians, but we know that at a later time a considerable portion of the supply was carried overland through Gaul to Massilia. Whether the voyage of Pytheas had any effect in contributing to bring about the diversion of this lucrative trade we have unfortunately no information. Whatever uncertainty still hangs around all that has been trans- mitted to us concerning the actual explorations of Pytheas. it is certain that he had one merit which distinguished him from almost all his contemporaries : he was a good astronomer, and was one of the first who made observations for the determination of latitudes, among others that of his native place Massilia, which he fixed with remarkable accuracy, so that his result, which was within a few miles of the truth, was adopted by Ptolemy, and became the basis of his map of the Western Mediterranean. Pytheas was also the first among the Greeks who arrived at any correct notion of the tides, and not only indicated their connexion with the moon but pointed out their periodical fluctuations in accordance with the phases of that luminary. Other observations concerning the manners and customs of the inhabitants of these remote regions are ascribed to him that are undoubtedly correct and tend strongly to prove that he had himself really visited them. Among these are the gradual disappearance of various kinds of grain as one advanced towards the north ; the use of fermented liquors made from corn and honey ; and the habit of threshing out their corn in large covered barns, instead of on open threshing-floors as in Greece and Italy, on account of the want of sun and abundance of rain. The fragments of Pytheas have been collected by Arvedson (Upsala, 1824) and by Fuhr (De Pythea Massiliensi, Darmstadt, 1835). Of the numerous treatises and dissertations on the subject see for those of earlier date Ukert's " Bemerkungen iiber Pytheas " (in vol. i. of his Geog. d. Griechen u. Homer, pp. 298-309), which contains an ^excellent summary of all that is known con- cerning tke author and his work. The question has been also discussed by Sir G. C. Lewis, in his Historical Survey of the Astronomy of tke Ancients (pp. 466-480, London, 1862), by Mr Bunbury, in his History of Ancient Geography (vol. i. chap. xv. sect. 2), and by Mr Elton, in his Origins of English History (London, 1882). A very elaborate but prolix and somewhat confused investiga- tion of the whole subject will be found in Miillenhoff's Deutsche Alterthums- kicnde (vol. i. pp. 211-497, Berlin, 1870). (E. H. B.) PYTHON, a genus of gigantic snakes inhabiting the tropical parts of Africa and Asia, and known in some parts of the British possessions by the name of " rock-snakes." On account of their general appearance, beautifully-marked skin, large size, and similarity of habits they are frequently confounded with the true boas of the New World and misnamed " boa -constrictors." They differ from them, however, by having a double row of scutes under the tail, pits in the shields round the margins of the upper and lower jaws, and teeth in the intermaxillary bone. Africa is inhabited by three species (Python sebae, P. regius, and P. natolensis), and Asia by two (Python molurus and P. retieulatus), the former of these two species being found on the continent of India and in Ceylon, the latter in the large islands of the Archipelago and in the Malayan Pen- insula. In Australasia and New Guinea similar snakes occur, but they are of much smaller size and differ in essential structural characters from the rock-snakes. These latter are among the largest of living reptiles ; although their dimensions and strength have been much exaggerated, specimens of 18 and 20 feet have been brought to Europe, and reliable statements of the occurrence of individuals which measured 30 feet are on record. Snakes of this size will easily overpower and kill one of the small species of deer or antelopes which abound in their native haunts, a sheep, or a good-sized dog ; but the width of their mouth would not permit them to swallow an animal larger than a half-grown sheep. The way in which they seize and kill their prey does not differ from that observed in num- Python retieulatus (India). erous other non- venomous snakes : after having seized their victim, they smother it by constriction, throwing several coils of the body over and round it. In swallowing they always commence with the head ; and, as they prey exclusively on mammals and birds, the hairs and feathers offer a considerable impediment to the passage through the narrow but distensible throat. The process of deglu- tition is therefore slow, although facilitated by the great quantity of saliva discharged over the body of the victim. During the time of digestion the snake is very lazy, and unwilling to move and to defend itself when attacked. At other times these animals are fierce enough, although always harmless to man if left unmolested. In captivity they seem to become used to those who attend upon them, but their apparent tameness is due rather to the depress- ing influence of a colder climate than to a change of their naturally excitable temper. Rock-snakes are mostly arbo- real, and prefer localities in the vicinity of water to which animals resort for the purpose of drinking. They move, climb, and swim with equal facility. It has now been well established by observations on specimens in a state of nature as well as in captivity that the female rock-snake incubates her eggs for about two months, at the end of which period the young are hatched, and probably remain under the protection of the mother for a few weeks longer. The snake collects the eggs into a conical heap, round which she coils herself, entirely covering them so that her head rests in the centre on the top of the cone. In this position the animal remains without food throughout the whole period of incubation, and an increase of the temperature between the coils of the snake has been ob- served in every case. PYX. See MINT, vol. xvi. p. 483.
