for the age assignment. It is obviously impossible in many 
cases to determine whether some species listed actually 
came from the Miocene or from the Oligocene, or from Upper 
Ordavdichans or Lower Silurian. No author could be suf- 
ficiently familiar with the precise age of all type locali- 
ties, many of which are still in question. Barrande's 
"Silurian" ostracoda of Bohemia came from various portions 
of the Paleozoice Some of these have been settled by later 
workers such as Pribyl, and in such cases I have taken the 
later assignment. In other cases, I have followed Barrande's 
assignment to the portion of the "Silurian" to which he 
assigned the species. Dr. Fe Me Swain under date of June 8, 
1954 has kindly written me: 
"Ulrich's tLower Silurian’ ostracodes are 
nearly all, if not all, post-Chazyan Ordovician 
(cf.Schmidtella)." 
For these genera I have therefore followed Swain, rather 
than Ulrich in the age cited. 
This volume is not an attempt to give a complete 
bibliography of ostracoda. Perhaps in future years, if 
current ostracod workers will kindly call my attention to 
papers which I might otherwise overlook, and if I can per- 
suade Dr. Stuart Levinson to join me in such an undertaking, 
thus making available the large ostracod library which he 
and the Humble Oil and Refining Company have amassed, we 
together might be able to come fairly close to completeness. 
Xvi 
