​GROOVE-TOOTHED SQUIRREL, a large and brilliantly coloured Bornean squirrel, Rhithrosciurus macrotis, representing a genus by itself distinguished from all other members of the family Sciuridae by having numerous longitudinal grooves on the front surface of the incisor teeth; the molars being of a simpler type than in other members of the family. The tail is large and fox-like, and the ears are tufted and the flanks marked by black and white bands.