ORDER OF MONOTEEMATA. 11 



(lelphes, wishing to show bj' this name that the reproductive 

 organs of these Mammalia, and the manner in which they accom- 

 phsh their generative functions, remind one, in different ways, of 

 what passes among birds. However, this expression was never 

 adopted, and we will preserve the first denomination, so as to 

 comply with what is usually accepted. 



The Monotremata resemble birds again in their mouth, which 

 is toothless, and which terminates in a sort of horny beak, of a 

 rather singidar form. 



They are like reptiles as far as the form of the shoulder is 

 concerned, for it presents, as in the Saurians (Lizards and Cro- 

 codiles), a double clavicle or collar-bone. 



In all other respects they are true Mammalia. They have 

 mammae, very rudimentary indeed, but which secrete a milky 

 fluid, destined to nourish their young. These glands are deprived 

 of externally visible udders and are consequently scarcely notice- 

 able, which explains how for a long time there were some who 

 denied their existence. The Monotremata are provided with four 

 unguiculated members ; their bodies are covered with hair, and 

 they have marsupial bones, like the animals which compose the 

 second order of Mammalia, although these bones, in their case, do 

 not support the pouch which is the distinguishing feature of the 

 latter. 



Much discussion has taken place on the question as to whether 

 the Monotremata are oviparous or viviparous. It has been well 

 proved now that they give birth to their yoimg alive ; but it 

 cannot be doubted that their mode of gestation differs greatly 

 from that of the ordinary viviparous animals. All naturalists agree 

 in saying that in this respect they resemble much the ovo- viviparous 

 Vertebrata, that is to say, those in which the egg is hatched in 

 the mother's body, by interior and direct incubation ; such are 

 the Viper among reptiles, and, among fishes, some of the Ray and 

 Shark tribe. 



Only two families of Monotremata are at present known : viz. the 

 Duckbill {Ornithorhynchus) and the Porcupine Ant-eater {Eclnd)ia). 

 The discovery of these strange animals onljr dates back as far as 

 the year 1722. The Ornithorhynchus and the Echidna inhabit 

 exclusively Tasmania (or Van Diemen's Land) and Australia, that 

 country so remarkable for the singularity of its fauna, and in 



