This snake does not exist in Guadeloupe. “In the islands in which it is found,” says Dr. Rufz de Lavison, “its presence makes itself felt even where man has built his dwelling and cultivates the soil. Because of it no one can carelessly lie down to rest in the shade of a tree; no one can walk in the woods or enter unconcernedly into the pleasures of the chase.” It is especially abundant in coffee and sugar plantations, and is met with from the sea-level up to the summits of the highest mountains in Martinique and St. Lucia. It not infrequently makes its way into human habitations, and is not uncommon in gardens, even entering those of the town of Fort-de-France. It does not seek its prey by day, but remains on the alert, always ready to bite. With open mouth, and fangs projecting forwards, it strikes with the rapidity of lightning. It swims in the rivers and moves over the ground with great speed. Oviposition takes place in July, and the young are hatched forthwith, the usual number being from about 50-60. It feeds upon lizards and rats, but also destroys a certain number of fowls and turkeys. All the large animals are afraid of it. Its bite is extremely dangerous, and causes about a hundred deaths in Martinique every year. In striking at its prey or at a man, the _Fer-de-lance_ throws back its head and opens its jaws widely, with the fangs directed forwards. It drives in its poison-teeth as with the blow of a hammer, and quickly draws back again. When very excited, it resumes its position and strikes afresh. It never becomes tame, but is capable of living a fairly long time in captivity. I have kept a number of specimens of it for more than two years, caged in my laboratory. (3) _L. atrox_ (Labaria).--Closely resembling _L. lanceolatus_, but bulkier; the enormous head is armed with powerful fangs, which are often more than a centimetre in length; 7 supralabial shields; scales in 25-29 rows, strongly keeled; 161-216 ventrals; 47-73 pairs of subcaudals. Colour brown, with dark cross-bands or triangular blotches, with the apices adjacent on the vertebral line; a dark streak from the eye to the angle of the mouth; belly yellowish-white, speckled with brown, or brown spotted with yellowish-white. Total length, 1,110 millimetres; tail 180. _Habitat_: from Central America to Peru and Northern Brazil. (4) _L. pulcher._--Two postocular shields and a subocular, separated from the labials by one series of scales; 7 supralabials; scales in 21 or 23 rows, strongly and tubercularly keeled; 156-172 ventrals; 58-64 pairs of subcaudals. Colour olive-grey, with brown, light-edged cross-bands, which are continuous or broken on the vertebral line; a light streak from the eye to the angle of the mouth; belly covered with minute confluent brown markings, with darker and lighter spots on the sides. Total length, 685 millimetres; tail 115. _Habitat_: Andes of Ecuador.