HYL.EOSACRUS. 



HYLOBATES. 



1M 



and sub-compressed ; hallux very strong, 



TurmU. It inhabit* the Island of Chiloe and Port 

 Otway. fa the Bay of I'sfta*. ('ZooL ProoV 1880-31.) 



I..C06AURU8, Dr. Mantell's name for an extinct Saurian dis- 

 ****nd by Urn in the fora* of Tilgate, and thane* termed the Forest- 

 Ltcard. the remains upon which this genus was characterised were 

 embedded in a block of stone 4| feet by 24 feet, and consisted prin- 

 cipally of bone* of the trunk. A chain of five cervical and five dorsal 

 vertebra with corresponding ribs, and four detached vertebra), were 

 TtaibU; sown* the coracoids aad omoplates of both sides. There 

 w* a peculiarity in the .tructure of the last-mentioned parts which, 

 fa the opinion of Dr. Mantel), warranted the separation of this Saurian 

 from all recent aad fossil genera ; for the Ilylaxuauriu had the omo- 

 plate* of a crocodile with the ooraooid* of alixard. There was also a 

 still more rxtnordmary osteologies! structure, consisting of a series 

 of spinous bony apophysea, which varied from 3 to 17 inches in length, 

 and from 14 to 7 inches in width. These maintained a certain paral- 

 lelism with the vertebral column, as if they had occupied a line along 

 the back. Dr. Ilantell suggested that these processes might be the 

 remain* of a derma! fringe or serration, with which, as in some recent 

 specie* of Saurian*, the back of the Forest-Lizard might have been 

 armed ; but he at the same time noticed many anatomical peculiarities 

 which led him to hesitate in determining positively that these parts 

 had formed such appendage*. He next entered upon a careful exami- 

 nation of the reason* why they could not be processes of the vertebra 

 Dr. Mantoll also discovered many derma! bones, which served to sup- 

 port the Urge Males, in the stone : he finally proposed the genus as 

 depending for it* character* on the peculiarity of the sternal apparatus 

 and the spinous processes. The paper in which the remains of this 

 Urge extinct Saurian were described WAS read before the Geological 

 Society of London in December, 1 832. 



Dr. Buckland (' Bridgewater Treatise ') is of opinion that this extinct 

 Saurian was probably about 25 feet long, and speaks of its most 

 p*"*- 11 " character a* consisting of the remains of the series of long 

 flat and pointed bone*, which. Dr. Buckland thinks, seem to have 

 formed an enormous derma! fringe like the horny spines on the back 

 of the modern Iguana. (Dr. Mantel], ' Geology of the South-East of 

 England,' 8vo, London, 1883.) 



The remain* of severs! specimens of this extinct reptile are now, 

 with the rest of Dr. Mantell'a collection, in the British Museum. The 

 original species described by Dr. Hantell has been named //. Owcni. 

 (Mantell. 'petrifactions and their Teachings.') 



HTLO'BATES (from Ao04np, wood-walker, or one that goes 

 through woods), Illiger's name for the Long- Armed Apes, or Gibbons. 

 The general characters of these Ape* a* to dentition and form agree 

 with thoM of the Orang* ; but there is some modification of the dental 

 system in the Gibbons, which have also longer anterior extremities 

 and have posterior callosities, though they have no tail. The vermi- 

 form appendix of the ccocum is also shorter. 



Dental formula : Incisors, j-; canines, ~; molars, .-=32. 



In the upper jaw the first incisor is large, terminated by a straight 

 BBC, worn obliquely within, and cut transversely by the impression 

 of the lower indaor; the second is smaller than the first, and worn 

 obliquely on the side of the canine, which is wider than it is thick, 

 trenchant on iu posterior border, and presents two longitudinal 

 farrows on it* interns! surface, separated from each other by a pro- 

 jecting rib,* the posterior furrow being larger and deeper than the 

 anterior one. The two next teeth are false molars, and the second is 

 rather larger than the first ; but both are composed of blunt tubercles, 

 on* on the external and the other, .mailer, on the internal border. 

 The three next molar*, which increase gradually in sixe from the first 

 to the last, have the saute form ; they an composed of four tubercles, 

 two of equal size on the external and two on the internal border, the 

 posterior tubercle bring smaller than that which precedes it : these 

 tubercles are formed by furrows, which divide the tooth unequally. 



In the lower jaw the first incisor is small, and terminated by a 

 straight line ; the see cod is rounded on it* external surface, terminated 

 fa a point, and strengthened on it* interns! surface by a longitudinal 

 rib. which thickens it in the middle. The canine is more equal in 

 JU dimension* than that of the other jaw, and i. terminated posteriorly 

 by a process or heel ; but it* internal surface presents also the two 

 furrows and the rib which are found in the other. The first false 

 molar, which is placed obliquely, ha* only a single point ; the second 

 ha* two, on* iaternal and the other external, situated nearer to the 

 anterior than to the posterior border. Three molar* succeed, which 

 Mnfrcaaivmly meres** in sice, and resemble each other. They present 

 tubercles, two of which are anterior, and three, disposed in a 

 rianep*, posterior. 



f. CuvUr take* this type of dentition from the Siamang, and says 

 that it U aUo found in the Wow- Wow and Onko. 



The height of the Gibbon* rarely exoseds four feet, and when they 

 are placed in an eract posture their upper extremities reach the 

 . 



The *p*efa> are found all over lujja .d ite islands. The forest* 

 Is //yfohrin AM** the cmnlnw .re mn.rk.blr 1on. 



are the haunts of these creatures, and they are rarely seen at a distance 

 from them. Gregarious, but shy and timid, they keep tip a li 

 concert, resembling in this respect in some degree the Howling 

 Monkeys of America, and having some of them guttural sacs like that 

 tribe. In the forest the activity of certain species is great, and they 

 make way on the trees with their long arms and lengthened feet most 

 rapidly ; but when surprised on open plain ground they are alto- 

 gether as helpless. Other species (the Siamang. for instance) appear 

 to be more sluggish ; but these make good use of their acute eyes and 

 ears, and are generally off before the enemy approaches near enough 

 for a capture. 



Teeth of JTyhkata, increased 1-Oth. F. Cnvicr. 



In confinement they are gentle, and seem capable of great attach- 

 ment to those who are attentive to them. Dr. liurrough gives a most 

 interesting account of three individuals of the species called Hoolock 

 (Ifylvbata Jlooloct), which he had an opportonity of observing iu that 



Wow- Wow (Ifylohntn ttfilit), male. 



state. One of them, a male, showed a most amiable and docile dis- 

 position ; and a young fetrmlo, which died early, was equally gentle 

 and pacific. The Siamang kept hy Sir Stamford Raffles was, according 

 to Dr. Horsfield, very tatnn and tractable, and was never happy unless 

 it was in the company of some person. Mr. George Bonnet gives 



