"Not exactly," replied their guide, with a smile. "It is a land-crab, which is very abundant on the Isthmus, and considered an excellent article of food. It is rapacious, like the crab generally, and comes fearlessly into the presence of man in search of a breakfast. These crabs devour the flesh of animals, and will often reduce a horse or ox to a heap of polished bones in a few hours. It will be well for you to tread carefully on the ground in the vicinity, as you never know when you will encounter a scorpion, tarantula, or centipede, or even a venomous snake. Occasionally we find large serpents of the constrictor species, but they are not as dangerous as the smaller reptiles and insects. The tarantula is a sort of hairy spider, quite pretty to look at, but so venomous that his bite causes death in a few hours. The natives have a belief that if a tarantula simply walks over the flesh without biting there is left a poisonous trail which causes rheumatic and other pains, lasting for years or perhaps for a lifetime. Catch one of these spiders and show it to a group of natives, and they will run shrieking away from you." [Illustration: EXHIBITING A TARANTULA.] The whistle of the locomotive put an end to the conversation, and recalled the young naturalists to the train. Fred observed a native with one foot bandaged across the toes, and asked what was the matter with him. "Probably jiggers," was the reply. "And please tell us what jiggers are?" "Its native name is _chigoe_," answered their guide, "and this has been anglicized into 'jigger.' Its scientific name is _Pulex penetrans_; it is a species of flea which deposits its eggs in the human body, especially under the skin of the foot or the nails of the toes. Its presence is indicated by a slight itching and subsequently by a membranous sac, like the head of a pin. This sac can be removed with a needle or by washing the feet with tobacco juice; if allowed to remain it causes an ulcer, and the victim will quite likely lose his toes. It is necessary to keep close watch to one's feet, and wash them frequently with strong soap or decoction of tobacco." [Illustration: HILLS NEAR THE RAILWAY.] Natural history gave place to more immediate matters as the train passed one of the points where excavations for the canal were going on. The scene was a repetition of that at Gatun, and needs no special description, but it naturally led to further conversation upon the great enterprise which was intended to unite the Atlantic and Pacific oceans. Fred asked how it happened that a canal through the Isthmus connecting North and South America was being constructed by Frenchmen and with French capital? [Illustration: MAP SHOWING HOW OCEAN ROUTES ARE SHORTENED BY THE PANAMA CANAL.]