ILLUSTRATED ZOOLOGICAL NOTICES. 347 



mammary glands, altogether disregards the consideration of 

 their viviparous production, and must, in strict logical accep- 

 tation, be taken to include all animals possessing these organs, 

 even when the function, which they were originally designed 

 to execute, no longer exists : for, in the progressive degrada- 

 tion of organic perfection, through successive groups, it is 

 a necessary condition of existence itself, that the function 

 should cease, either simultaneously with the organ, or before 

 it is obliterated ; and this latter phenomenon is so universal- 

 ly the case with regard to all other organs and functions, that 

 it ought not to be accounted matter of surprise in the present 

 instance. 



The Monotremata must therefore be regarded as a subor- 

 dinate group of mammals, but whether of primary or of se- 

 condary value, whether entitled to rank as an order or only 

 as a family, is an inquiry which admits of more reasonable 

 doubt. For my own part, as I consider the existence of the 

 marsupial bones to be the simple and only unexceptionable 

 character of the group, to which they are peculiar, I prefer 

 considering the Monotremata as a subordinate group, or fa- 

 mily, of this order, rather than elevating them to an indepen- 

 dent and equal rank, or associating them with a different or- 

 der. It is true indeed, that, strictly speaking, they come 

 equally within the definition of M. Cuvier's Edentata, but if 

 approximated to this order rather than to the other marsupi- 

 als, the integrity and logical simplicity of the latter group is 

 destroyed ; for these, as already observed, depend, not upon 

 the existence of the abdominal pouch, which is not common 

 to all the species of animals included in the present order, 

 but properly upon that of the marsupial bones. 



Art. IV. — Illustrated Zoological Notices. By Edward Charles- 

 worth, F.G.S. 

 {Continued from page 248). 



1. On a Specimen of the Lower Jaw of the Mammoth. 



2. On a Tooth of the Genus Otodus, Agassiz^from the London Clay. 



3. On a Fossil Zoophyte from the Kentish Chalk, inclosing a Cidaris. 



The fossil elephant's jaw represented in the accompanying 



It appears from this extract that Professor Agardh, like M. De Blain- 

 ville, is disposed to view the marsupials as forming a distinct class, inter- 

 mediate between mammals and birds ; I have already stated my reasons 

 for dissenting from this opinion. 



