LIFE OF FLOWER 107 



Flower's attack on these conclusions was commenced 

 by a paper which appeared in the Zoological Society's 

 Proceedings for 26th January 1864, entitled "On the 

 Optic Lobes of the Brain of the Echidna," in which it 

 was conclusively demonstrated that these structures 

 resembled those of the higher mammals in being four- 

 lobed. 



More important still was his memoir " On the Com- 

 missures of the Cerebral Hemispheres of the Marsupialia 

 and Monotremata, as compared with those of the 

 Placental Mammals," which was published in the Philo- 

 sophical Transactions of the Royal Society for 1865. In 

 this was shown, it was thought, the existence in both 

 monotremes and marsupials of a distinct, although very 

 small, corpus callosum connecting the two hemispheres 

 of the brain ; the anterior commissure, which in the 

 higher mammals is the smaller connecting band, being in 

 this instance much the larger. 



Recent researches have, however, tended to show 

 that Owen was after all right in denying the existence 

 of a corpus callosum in the latter groups. Even allow- 

 ing for this correction, the result of this important 

 paper was to discredit among all zoologists capable 

 of forming an adequate opinion on the subject Owen's 

 proposed fourfold division of the Mammalia into Lyen- 

 cephala, Lissencephala, Gyrencephala, and Archen- 

 cephala. And these terms have now completely 

 disappeared from zoological literature. 



In those days it required no considerable amount of 

 courage to attack a man of Owen's established social 

 and scientific position on an important subject like this ; 

 and Flower's triumph was therefore the more con- 



