THE ANNALS 



AND 



MAGAZINE OF NATUEAL HISTORY. 



[FIFTH SERIES.] 



No. 95. NOVEMBER 1885. 



XXX. — Critical Observations on Prof. Leidy''s ^^ Freshwater 

 RMzopods of North America^'' and Classification of the 

 Rhizopods in general. Bj Surgeon-Major Wallich, M.D. 



Feom the standpoint of the evolutionist any system of classi- 

 fication to be strictly natural must be based exclusively on 

 such characters as are indicative of physiological advance in 

 the class of organisms to which it is applicable j and, a fortiori j 

 every system not so based, and which, in its application, is not 

 even coincident with readily observable physiological advance, 

 must necessarily be looked upon as retrogressive and mis- 

 leading. 



With such a self-evident axiom for our guidance it will 

 probably be admitted by every biologist who is well read -up in 

 the scientific literature of the Rhizopods that in no class of the 

 Protozoa has multiplication of genera and species been carried 

 to a pitch so reckless, and certain, if left unchecked, to plunge 

 the nomenclature of the entire class into a state of inextri- 

 cable confusion. 



The plea most frequently urged in justification of this 

 mania for species-manufacture is that it is essential for the 

 purpose of identifying particular forms. But those who rely 

 on this plea seem to forget that identification of mere varieties 

 does not help us in identifying types, and therefore becomes 

 one of the most vexatious obstacles in the way of natural 

 classification ; the greater the tendency to unlimited variation 



Ann. & Mag. N. Hist. Ser. 5. Vol. xvi. 22 



