154 HYLOBATES 



Pegu and Arakan, to Tenasserim up to 3,500 feet, and the Malay 

 Peninsula H. lar has its range. In Siam H. leucogenys and H. 

 PILEATUS are found, the latter also going to Cochin China, through 

 Cambodgia. 



In Tonkin at Lai-chee, near the Yunnan border H. henrici was 

 procured, and H. nasutus, which is also a native of the Island of 

 Hainan. In Annam H. gabrielli has been obtained. In Sumatra we 

 have H. agilis; and H. leuciscus in Java. Borneo contains but one 

 species remarkable for the wonderful variation in the color of its 

 coat, H. concolor; and attributed to Sulu Island is a doubtfully 

 separable form H. funereus. One very doubtful form from an 

 unknown locality remains, H. fuscus. 



KEY TO THE SPECIES. 



A. General color black. 



a. Color entirely black H. nasutus. 



b. Frontal band white H. hoolock. 



c. Eyebrows, whiskers, beard, hands and feet white H. lar. 



d. Top of head, occiput and line down back of neck 



black H. henrici. 



e. Area below ears, and throat beneath chin white . H. leucogenys. 



f. Area below ears, and throat beneath chin ochra- 



ceous H. gabrielli. 



B. General color uniform gray H. leuciscus. 



C. General color buff or pale brown H. agilis. 



D. General color buff and black or grayish and black. .H. pileatus. 



E. General color brown and black H. concolor. 



F. General color grayish white H. funereus. 



G. General color dirty brown H. fuscus. 



The above Key, excepting H. henrici, describes the typical style 

 only of the recognized species, all of which are subject to variation, 

 some of them to a most extraordinary degree, the black ones having 

 albinistic individuals in many degrees of change and variety of tints ; 

 the paler forms on their side having melanistic representatives wholly 

 or in part, so that a collection of members of this genus presents a 

 bewildering array of many colored or unicolored individuals. 



These examples, adverse in the hues of their coats to the typical 

 style, are not confined to particular localities, but are found, members 

 of the same troop, and frequently in the same place in which the type 



