IGO^ FOURTH REPORT 1834. 



mills, I may ol)serve, thiit it is not mj^ intention to do more than to 

 convey a general notion respecting the state of our knowledge 

 of the principal groups contained in them. At the same time 

 I shall notice any recent researches which appear to throw 

 light on their affinities, or to illustrate more clearly either their 

 external or internal characters. Of these last I confine myself 

 to such as are of immediate importance to zoology. 



I. Vertkbrata, Cuv. 



1. Mnmmalki. — Cuvier and GeofFroy greatly contributed to 

 our knowledge of this class during the early part of the present 

 century. The former by his investigation of fossil species sup- 

 plied us with many new forms, serving in several cases as links 

 to connect groups which before were widely separated. He 

 also found it necessary, in order to determine the above with 

 accuracy, first to examine more closely the structure of such 

 species as are living at the present day. Owing to this circum- 

 stance his Ossemcns Fossiles has conferred a lasting benefit on 

 this department of zoology. His researches served to elucidate 

 the history of numberless genera, and even led to the establish- 

 ment of one entire family*, of which the true affinities had pre- 

 viously been quite misunderstood. Geoff"roy also laboured much, 

 and indeed has continued to do so to the present time, at the 

 natural arrangement of these animals. His various memoirs in 

 the Annales dii Museum and other French periodicals, more 

 particularly those on the Marsujrialia, Cheiroptera, and Qund- 

 rumana ; his splendid work also, the Histoire des 3Iammiferes, 

 undertaken conjointly with M. Fred. Cuvier, are well known, and 

 deservedly celebrated. Yet notwithstanding the laborious re- 

 searches of these, and many other eminent zoologists, perhaps 

 it is not advancing too much to affirm, that we are still in many 

 cases far from understanding the real affinities of the Blanimalia, 

 and less agreed about the primary groups into which they ought 

 to be distributed, than in the instance of some other classes lower 

 down in the systemf. This will appear by referring to the 

 principal classifications which have been published since that of 

 the Regne Animal. Cuvier, in the work just mentioned, admits 

 the following eight orders : Bimana, Qiiadnimana, Ferce (Car- 

 nassiers), Rodentia, Edentata, Pachydermata, Ruminantia, 



* The Herhioorous Cetacea. 



t This probably arises in a great measure from the paucity of forms which 

 this class presents compared with others. Mr. MacLeay has observed, {Aiinul, 

 Javan., p. xi.) that we arc more likely to detect the natural arrangement 

 amongst Insects, from the circumstance of their presenting such a multiplicity 

 of species, than in any other part of the system. 



