ORDERS OF MAMMALIA. 315 



America. The third family includes only the well-known 

 Hedgehogs, which have the power of rolling themselves into 

 a ball at the approach of danger, and which have the upper 

 surface of the body covered with short prickly spines, forming 

 a protective armor. The common European Hedgehog (Eri- 

 naceus Europceus) is the type of the family, but other species 

 occur in Africa and India. The "Tenrecs" (Centetes) of 

 Madagascar are closely allied to the Hedgehogs, but have no 

 power of rolling themselves up. The " Banxrings " ( Tupaia) 

 of the Indian Archipelago have a long, compressed tail, and live 

 mostly in tees. 



Before passing on to the next order, a few words must be 

 said about a curious transitional form, which has been alter- 

 nately placed in the Cheiroptera, the Insectivora, or the 

 Quadrumana, or has been regarded as the type of a separate 

 order. The animal alluded to is the so-called Flying Lemur 

 ( Galeopithecus volitans), of which more than one species is 

 known as inhabiting the Indian Archipelago. The leading 

 characteristic in this singular animal is the possession of a fly- 

 ing-membrane, which extends as a broad expansion from the 

 nape of the neck to the arms, from the arms to the hind-legs, 

 and from the hind-legs to the tail. The fingers are not elon- 

 gated, and do not support a " patagium," so that the animal 

 has no power of true flight, but can simply take extended 

 leaps from tree to tree. The Galeopithecus lives chiefly upon 

 small insects and birds, and it should, probably, be regarded 

 as an aberrant form of the Insectivora. 



ORDER XIII. QUADRTJMANA (Lat. quatuor, four ; manus, 

 hand). The thirteenth order of Mammals is that of the Quad- 

 rumana, comprising the Apes, Monkeys, Baboons, and Le- 

 murs. The characteristic of this order is that the innermost 

 toe (great-toe) of the hind-limbs can be opposed to the other 

 toes, so that the hind-feet become prehensile hands. The term 

 " opposed " simply implies that the toe can be so adjusted, as 

 regards the extremities of the other toes, that any object can 

 be grasped between them, just as the thumb of the human 

 hand can be " opposed " to any of the fingers. The fore-feet 

 may be destitute of a thumb, but, when this is present, it too 

 is generally opposable to the other digits, so that the animal 

 becomes truly four-handed or " quadrumanous." 



The Quadrumana are divided into three very natural sec- 

 tions, separated from one another both by their anatomical 

 characters and their geographical distribution. 



