NOTICES OF NEW BOOKS. 357 



than with regard to the classification of Birds (see Zool. 1894, 

 pp. 469-470), owing, no doubt, in a great measure to the difficulty 

 of determining what features should be regarded as of primary 

 importance. 



The Killer or Grampus, Orca gladiator. 



Mr. Lydekker has thought it " advisable," as he tells us 

 (p. 303), "in a popular work of the present nature to revert to a 



Eisso's Dolphin, Grampus griseus* 



modification of a scheme proposed some years ago by Dr. Sclater. 

 Including certain extinct forms, Birds, according to this scheme, 

 may be divided into twenty-five groups, of which the first twenty- 

 two may be reckoned orders — such orders, be it understood, 

 being for the most part far less distinct from one another than 

 are those of Mammals. 



