They are extremely delicate animals, although their fur is thick, and, in some kinds, long. They require a considerable temperature and very pure air; hence, although many have been brought to Europe, and exhibited to the delight of thousands, they do not live long, dying usually from consumption or from some lung disease. In the British Museum there are several groups of stuffed specimens of them, and also many skulls and skeletons, and a cursory examination of the first will prove that it is very difficult to distinguish one kind from another, for in the same kind, or species, there is a great variety of colour, and a different individuality in the two sexes and young. It has happened that the same kind has been called by several names by different observers, and it is only when the skeleton has been examined with the stuffed specimen that a satisfactory distinction between the species or kinds has been made. Evidently, the whole of these long-armed Apes, with small heads and callosities on the seat, are separable into two divisions. In one the animals are larger than the others, and have a very singular adaptation of the foot for rapid movement amongst the boughs, and they have air-pouches; and in the second the animals are smaller, and have the toes free, and have no pouches. So the genus _Hylobates_ is divided into two divisions: 1. The Siamangs. 2. The True Gibbons. THE SIAMANG.[19] Sir Stamford Raffles brought the Siamang prominently before the scientific world, and noticed the curious manner in which some of the toes were united, and he considered that this was to enable them to swing rapidly from branch to branch during their ordinary movements in the forest, when any stretching out of the fingers might be dangerous and produce a fall. But in this, as in many others, we owe to Mr. Wallace thanks for a concise description of the habits of the creature, which, from having its toes partly joined, has been named, _Syndactylus_, from the Greek words σὺν and δάκτυλος, which mean “together” and “finger.”