terms originally ascribed to ostracods, but later trans- 
ferred to Conchostraca or other groupse It is interesting 
to note that in the 75 years following O. F. Mtillerts 
description of Cypris, in 1776, only about a dozen taxonomic 
terms were developed for the ostracoda. The past hundred 
years have seen the number of terms grow to approximately 
1200. Agnew 1942, pe756 noted that Bassler and Kellett 1934 
listed less than 200 paleozoic genera, and listed 167 
additional genera or subgenera from the Paleozoic for the 
next 8 years. Levinson 1953,p-5l1 noted the addition of 71 
new genera and subgenera during the years 1950-1952, remark- 
ing that it was a large increase from the 31 new genera and 
subgenera in the years 1947-1949. The rate is still increas- 
ing. Unfortunately many of the new genera turn out to he 
homonyms or synonymse It is hoped that this Handbook will 
make available to authors of new genera much needed informa- 
tion which will tend to reduce the number of unnecessary names. 
It should be pointed out that the age given for each 
fossil genus is in most cases the age assigned by the original 
author. I have attempted to give the age assigned to the 
type species, in case the type species was described by an 
earlier author. In a number of cases the author did not give 
the age, but merely the formation or locality from which it 
was described. In such cases for American ostracod genera, 
I have attempted to follow Wilmarth's Lexicon of geologic 
names of the United States, U. Se. Geol. Survey Bulletin 896. 
XV 
