OEDER OF MONOTEEMATA. 



"Natura nonfacit saltiim" was a dictum of LinnaBus, wliich means 

 that there exist between all living beings gradations and transi- 

 tions, which render a rigorously exact classification very difficult, 

 and sometimes impossible. We said in the preceding volume of 

 this work: "Nature makes transitions, Naturalists make divisions." 

 For, in fact, there do not exist in organised beings such accurately 

 marked divisions as naturalists have invented for facilitating 

 their studies. All is connected and linked together in creation. 

 Creatures pass insensibly, without fits or starts, from the simplest 

 to the most complex organization ; from the rudest to the most 

 advanced. Nature arranges these transitions with infinite art ; 

 she softens down, by intermediate tints, the crudity which might 

 result from, the contrast of very different colours. All the parts 

 of the grand work are thus blended together with a sublime 

 harmony, which fills the soul of the observer with a well-merited 

 admiration. We shall find in the first order of Mammalia a 

 striking confirmation of these ideas.* The Monotremata resemble 

 at the same time Mammalia, Birds, and Reptiles. In the Monotre- 

 mata, as in birds, the urine, the excrements, and the products of 

 generation, are evacuated by one common orifice, named the cloaca. 

 The name Monotremata, given them by M. Geofiroy Saint- Hilaire, 

 very well expresses this principal peculiarity of their organiza- 

 tion : it signifies one single hole {f_itnm<:, single, alone ; Tprj/na, 

 an orifice). Nevertheless this characteristic alone would not 

 suffice to enable us to recognise the animals which we are now 

 occupied in considering ; for this is found equally among certain 

 of the Edentata. And so De Blainville thought that we ought 

 to substitute for the preceding denomination that of Ornitho- 



* It must not be supposed, however, that in the existent condition of the animal 

 Icing-dom, there is a complete intergradation of all forms of life, such as the author 

 apparently contends for. This is very far fi-om being the truth — Ed. 



