PART II: INTRODUCTION. (23 
Paris-Moscow Code, 1889-92.—Art. 42. Les noms de famille sont 
formés en ajoutant la désinence zd au radical du genre servant de 
type. On dénommera les subdivisions de la famille en ajoutant la 
désinence Zn au nom du genre servant de type. 
Art. 43. Un nom de famille doit disparaitre et étre remplacé, si le 
nom générique, aux dépens duquel il était formé, tombe en synonymie 
et disparait lui-méme de la nomenclature. 
Art. 46. La loi de priorité est applicable aux noms de familles ou de 
groupes plus élevés, tout aussi bien qu'aux noms de genres et d'espéces, 
à la condition qu'il s’agisse de groupes ayant méme extension. 
Report of the Fourth International Congress, 1598.—Section 31. 
The name of a family is formed by adding the ending Zd:e, the name 
of a subfamily by adding ze to the root of the name of its type genus. 
Section 32. The name of a family or subfamily should be changed 
when the generic name serving as type is changed. 
APPLICATION OF RULES. 
In one respect the various codes are in complete agreement, viz, in 
declaring that families should be based on valid genera, and should 
have the termination ‘id,’ while subfamilies should end in ‘ ine.’ 
But as to the names to which these terminations are to be applied there 
is room for considerable diversity of opinion. The Stricklandian Code 
declares that the family should be based on **the earliest known or 
most typically characterized genus;” the A. O. U. Code on the ** tenable 
name of some genus, preferably the leading one;” the International 
Code, ‘‘au radical du genre servant de type." Again the A. O. U. 
Code declares that the law of priority applies only where names are 
strictly synonymous and is at best only partially operative, while the 
International Code states that the law is applicable to the names of 
groups of the same extent, but implies that it 1s not mandatory as in 
the case of genera and species. 
A few examples will show the difficulty of applying these rules. 
The chinchillas form a homogeneous group of three genera, the visca- 
chas, Véseaceza, 1816 or Lagostomus, 1828; the true chinchillas with five 
toes on the front feet, Chinchilla, 1829, or Erzomys, 1829; and the four- 
toed chinchillas, Zagidium, 1833. The first is restricted to the pampas 
of Argentina and the last two are confined to the Andes of Peru and 
Chile. Thus there are five names 
FEriomys, and Lagidivwm—tor three genera, and four of these five generic 
names have been used as the basis of the four corresponding family 
names, Viscachides: 1842, Chinchillid:e. 1533, Eriomvid: 1854, and 

Viseaccia, Lagostomus, Chinchilla, 

majority of the genera which that family has included, and that genus is inserted 
in another family. Also, when a large number of genera are redistributed into fam- 
ilies, widely differing in their limits from those in which they had previously been 
known. In either of these cases, liability to error may be so great as to render a 
new name desirable." (Dall, Rept. Am. Ass. Adv. Sci., 1877, p. 27.) 
