24 
Reduced to the last analysis, the systematists see themselves forced 
to adopt the oldest available name in any given case, or to leave it to 
the personal wishes of ever} 7 author to use any name he prefers. The 
author who prefers the latter alternative can not, however, consist- 
ently criticise an author who “prefers” to use the earliest available 
name. 
Thus, we use Ascaris , 1758, in preference to Fusaria , 1800; Taenia 
saginata , 1782, in preference to Taenia mediocanellata , 1852; Taenia , 
1758, in preference to Alyselminthus , 1800, and dialysis, 1803; Plas- 
modium malariae , 1881, in preference to Plasmodium golgii , 1902; etc. 
APPLICATION OF THE LAW OF PRIORITY. 
Art. 26. The tenth edition of Linne’s Sy sterna naturae , 1758, is the 
work which inaugurated the consistent general application of the 
binary nomenclature in zoology. The date 1758, therefore, is accepted 
as the starting point of zoological nomenclature and of the law of 
priority. 
Discussion. — The adoption of the tenth edition of the Sy sterna na- 
turae has its practical basis, namely, this was the first work in which 
the binominal system was consistently applied to all known animals, 
hence all groups .in zoology have the same date (1758) as starting point 
for their nomenclature. Any earlier names used as generic or specific 
names in that edition take the date of 1758, while earlier names rein- 
troduced into zoology after January 1, 1758, take priority from such 
date of reintroduction. 
Art. 27. The law of priority obtains and consequently the oldest 
available name is retained: 
a. When any part of an animal is named before the animal itself; 
b. When the larva is named before the adult; 
c. When the two sexes of an animal have been considered as dis- 
tinct species or even as belonging to distinct genera; 
d. When an animal represents a regular succession of dissimilar 
generations which have been considered as belonging to different 
species or even to different genera. 
Discussion. — Article 27 is of considerable importance in medicine 
since names of “larval” forms (or alternating generations) as well as 
names of adults must be considered. Thus, Echinococcus , 1801, must 
take precedence over Ech inococcifer, 1858, although the former was 
established upon a “larval” stage, the latter upon a sexually mature 
stage. 
Art. 28. A genus formed by the union of two or more genera or 
subgenera takes the oldest valid generic or subgeneric name of its 
components. If the names are of the same date, that selected by the 
first reviser shall stand. 
