360 MR. OWEN ON THE GENERATION OP THE MARSUPIAL ANIMALS. 



vascular, a corresponding simplicity of the cerebral organ ; and accordingly we do 

 find that the brain in the Cheiroptera and Rodenfia resembles that of the Bird in 

 the smoothness of the cerebral hemispheres and their limited extent, the cerebelltim 

 being wholly uncovered by the cerebrum throughout these orders *. 



Among the Marsupiata, the Opossums and Dasyures present a still simpler form of 

 the brain, the cerebral hemispheres being equally devoid of convolutions as those of 

 the Beaver, and leaving the bigeminal bodies as well as the cerebellum uncovered : 

 the fissure also which separates the olfactory tract from the superimposed cerebral 

 mass, instead of being inferior, as in the Rodentia, is here lateral : and, lastly, the 

 proportions which the thickness of the medullary covering bears to the extent of 

 the lateral ventricles is less than in any other mammiferous order. 



With respect to the brain of the Kangaroo, it must be observed, that although 

 shortly after birth it resembles in structure the brain of the lowest Vertehrata, yet it 

 afterwards assumes a more complex form than that of the Opossums or Dasyures, there 

 being a few symmetrical anfractuosities upon the cerebral hemispheres, which also 

 cover a greater proportion of the bigeminal bodies : the hemispheres are, however, 

 more contracted anteriorly, and have a smaller size, in proportion to the body, than 

 in those of the Rodentia. ♦ 



The inferiority of the brain, then, in connexion with the other points of resem- 

 blance to the inferior vertebrate classes which may be traced through the orga- 

 nization of the marsupial quadrupeds, seems at present to be the phenomenon 

 most intimately connected with their generation. Those which I have had the 

 opportunity of observing alive at the Zoological Gardens (and there are at present 

 species of Dasyurus, Didelphys, Phalangista, Petaurus, Hypsiprymnus, Macropus, and 

 Phascolomys,) are all characterized by a low degree of intelligence ; nor can I learn 

 that they ever manifest any sign of recognition of their keepers or feeders. Another 

 character, no less uniformly belonging to them, is the want of a power of uttering 

 vocalized sounds. When irritated they emit a wheezing or snarling guttural sound ; 

 that of the Dasyurus ursinus is the clearest, and is the nearest approach to a growl. 

 Mr. Harris, however, states, that in addition to this noise, the Ursine Opossum utters 

 a kind of hollow barking. The Thylacinus cynocephalus, or large Dog-faced Opossum, 

 he observes, utters " a short guttural cry, and appears exceedingly inactive and stupid, 

 having, like the owl, an almost constant motion with the nictitating membrane of the 

 eye-f ." The Wombat, when irritated, emits a loud hiss which forcibly reminds one of 

 that of the Serpent. The noise emitted by the Kangaroo under similar circumstances 

 is equally remote from a vocalized sound ; the necessary apparatus for producing 

 which Cuvier;}: long ago observed to be wanting in the larynx of this animal. 



* It is also in this order that the double superior cava is most frequently found, after the Marsupiata ; and the 

 Elephant, whose other affinities to the Rodentia CuviERhjis especially remarked, resembles them in this respect, 

 t Linnean Transactions, vol. ix. p. 173. 

 X Lemons d'Anat. Comp, iv. p. 509. 



