Page:Notes on the Slow Lemurs.pdf/5

. species included under A in the following key are closely related, the same is true of those under and C and C′.

Nachtrieb’s name menagensis for a Philippine Lemur, which he did not place in any genus, I have not considered, being unable to obtain further information regarding it than is given in the original description, which is insufficient to determine its generic place, although it probably belongs to this genus or an allied one.

A. Temporal ridges not meeting or approximating each other in old age, but forming two parallel ridges on top of skull; no specimens, not even newborn young, show more than one incisor on each side of upper jaw. B. Mastoid and audital bullæ not inflated; half ring of bone forming outer and lower border of orbit, broad and heavy. Underparts whitish. Borneo. B′. Mastoid and audital bullæ moderately inflated; half ring of bone forming outer and lower border of orbit, narrow and light. Underparts ochraceous buffy. Banka. A′. Temporal ridges meeting or approximating each other in old age, eventually forming a sagittal crest on top of skull; most adults show two incisors on each side of upper jaw, and young always do. C. Lines from crown of head to eyes and ears only faintly marked or obsolete. Larger, greatest length of skull less than 63 mm. D. Lines from crown of head to eyes and ears practically obsolete; general color of head, neck, and anterior part of body clear gray. Siam and Cochin China. D′. Lines from crown of head to eyes and ears present but indistinct; general color of head, neck, and anterior part of body not clear gray, merely lighter than general color of upper parts. Eastern Borneo and Burma. C′. Lines from crown of head to eyes and ears well marked and conspicuous. Smaller, greatest length of skull about 58 mm. E. Dorsal stripe bordered on either side, in neck and upper back, by a distinct gray area. Java. E′. Dorsal stripe not bordered on either side in neck and upper back by a distinct gray area. F. General color of upper parts intense and rich; hands, feet, and ears dusky. Natuna islands. F′. General color of upper parts not so intense or rich; hands, feet, and ears not dusky.