MARSUP1ALIA. 109 



wards the CETACEA. The earliest mammiferous animals whose 

 remains are found in the secondary and tertiary formations, are 

 those of this order. 



Sub-order MONOTREMATA, (Gr. /novos, monos, one ; r^^a, trema, 

 perforation.) The animals of this sub-order have given occasion 

 to naturalists for much discussion concerning their proper affini- 

 ties and their appropriate position among the MAMMALIA. They 

 are truly unique, both in their external form and their anatomi- 

 cal and internal arrangements, the details of which cannot be 

 given in this work. We will only say that "in the form of the 

 skull, the construction of the shoulder and the breast-bone, but 

 particularly in the whole reproductive system of organs, the 

 Monotremata present a manifest departure from a mammalian 

 type, and a corresponding approach to that of the oviparous Ver- 

 tebrce, tending to the reptiles more than to the birds." But how- 

 ever anomalous, it is evident they should have a place among the 

 mammals ; and also, though without any external pouch, that 

 the marsupial bones in the skeleton require that they be placed 

 next in order to the Marsupialia, "of which they constitute the 

 lowest and most aberrant type." 



These singular animals have no true teeth, but those of one 

 genus have horny substances in the jaw which represent those 

 organs. The muzzle is prolonged into a flat beak, more or less 

 like" that of a duck ; the eyes are small ; the ears are merely 

 minute orifices and without any external conch ; the limbs are 

 short and strong, suited for digging ; the feet have each five toes, 

 furnished with stout claws, and on the hind foot is a kind of sharp 

 spur. 



The order includes but two genera, viz. ; Echidna and Orni- 

 thorhyncus. Both are found exclusively in New Holland and 

 Van Diemen's Land. 



Echidna, (Gr. "e%iSva, echidna, a fabulous monster or viper.) 

 Of this there is but one species, changing its name vvi'th the varia- 

 tions of its clothing at different seasons, viz. : E. histrix, (G*.wr$, 

 a porcupine,) to E. setosa, (Lat. bristly.) The muzzle of this ani- 

 mal is elongated and slender, terminated by a small mouth, having a 

 long extensile tongue, similar to that of ant-eaters and pangolins ; 

 it is, however, more beak-shaped. The skin of this beak is thick 

 and without hair. The animal has no teeth, but the palate is 

 armed with many rows of small spines, directed backwards. 

 The feet are very large, robust, and armed with claws, being 

 formed for opening ants' nests. The upper surface of the body 

 and of the sh^rt tuberculous tail is covered with stout and strong 

 spines, intermingled with stiff, bristly hairs, and when alarmed, 



