356 THE ZOOLOGIST. 
of Pied and Yellow Wagtails given on Plates IV.—VIIL., it needs 
a nice discrimination to separate Motacilla lugens from M. 
ocularis, hodgsoni from personata, or borealis from cinereicapilla. 
Many authors separate generically the Yellow Wagtails from the 
Pied ones, bestowing upon the former the generic term Budytes : 
but Mr. Sharpe, we observe, calls them all Motacilla. At p. 457 
he says :—‘“‘ I have united the Field Wagtails (Budytes) with the 
Water Wagtails (Motacilla), as their separation does not appear 
to me to depend upon any structural character. A study of the 
whole of the Wagtails teaches us that although European 
forms might be divided under the above headings, there are 
certain intermediate species, such as M. flaviventris, which unite 
these two supposed genera.” 
Again, the generic differences between Motacilla and Anthus 
are so slight, that Mr. Sharpe would place them in the family 
Motacillide, instead of adopting, as Dr. Coues does, two sub- 
families, Motacilline and Anthine, a subdivision which Mr. 
Sharpe thinks strictly applicable only to the American species. 
His ‘“‘keys” to the genera and species are ingeniously con- 
structed, and although here and there one may detect a slight 
inconsistency or slip of the pen, on the whole they must be said 
to furnish useful aids to identification, and obviously represent a 
considerable amount of labour, and the handling of an enormous 
number of specimens. If Mr. Sharpe’s views are not always 
acceptable to ornithologists, they are at least deserving of atten- 
tive consideration as the outcome of the study of an unrivalled 
collection. 
Comparative Anatomy and Physiology. By F. Jurrery Bett, 
M.A., Professor of Comparative Anatomy at King’s 
College. Post 8vo, pp. 550, with 229 engravings. 
London: Cassell & Co. 1885. 
In this useful volume, one of a series of Manuals for Students 
published by Messrs. Cassell & Co., we have a guide to Com- 
parative Anatomy and Physiology written on somewhat new 
lines. The author points out that as there has been an evolution 
of organs as well as of animals, if we desire to understand the 
most complicated organs, we must first know the structure 
of such as are more simply constituted. With this object he has 
