[Footnote 1: Down to a very late period, a large and somewhat repulsive-looking monkey, common to the Malabar coast, the Silenus veter, _Linn_., was, from the circumstance of his possessing a "great white beard," incorrectly assumed to be the "wanderoo" of Ceylon, described by KNOX; and under that usurped name it has figured in every author from Buffon to the present time. Specimens of the true Singhalese species were, however, received in Europe; but in the absence of information in this country as to their actual habitat, they were described, first by Zimmerman, on the continent, under the name of _Leucoprymnus cephalopterus,_ and subsequently by Mr. E. Bennett, under that of _Semnopithecus Nestor (Proc. Zool. Soc._ pt. i. p. 67: 1833); the generic and specific characters being on this occasion most carefully pointed out by that eminent naturalist. Eleven years later Dr. Templeton forwarded to the Zoological Society a description, accompanied by drawings, of the wanderoo of the western maritime districts of Ceylon, and noticed the fact that the wanderoo of authors (S. veter) was not to be found in the island except as an introduced species in the custody of the Arab horse-dealers, who visit the port of Colombo at stated periods. Mr. Waterhouse, at the meeting (_Proc. Zool. Soc._ p. 1: 1844) at which this communication was read, recognised the identity of the subject of Dr. Templeton's description with that already laid before them by Mr. Bennett; and from this period the species in question was believed to truly represent the wanderoo of Knox. The later discovery, however, of the P. ursinus by Dr. Kelaart, in the mountains amongst which we are assured that Knox spent so many years of captivity, reopens the question, but at the same time appears to me to clearly demonstrate that in this latter we have in reality the animal to which his narrative refers.] Each separate species has appropriated to itself a different district of the wooded country, and seldom encroaches on the domain of its neighbours. 1. Of the four species found in Ceylon, the most numerous in the island, and the one best known in Europe, is the Wanderoo of the low country, the _P. cephalopterus_ of Zimmerman.[1] It is an active and intelligent creature, not much larger than the common bonneted Macaque, and far from being so mischievous as others of the monkeys in the island. In captivity it is remarkable for the gravity of its demeanour and for an air of melancholy in its expression and movements, which is completely in character with its snowy beard and venerable aspect. Its disposition is gentle and confiding, it is in the highest degree sensible of kindness, and eager for endearing attentions, uttering a low plaintive cry when its sympathies are excited. It is particularly cleanly in its habits when domesticated, and spends much of its time in trimming its fur, and carefully divesting its hair of particles of dust. [Footnote 1: Leucoprymnus Nestor, _Bennett_.]