LYMNZIDZ OF NORTH AMERICA. IX 
is a wide field for much valuable work in this direction. In Chapter 
III the geographical distribution of the family is discussed and a new 
division of North America into faunal areas is proposed. The tables 
of comparative distribution will doubtless prove of interest to students 
of this phase of the subject. The discussion of the post- and pre-glacial 
distribution is far from being as full or complete as could be wished, 
but seems to be the best that can be presented in the light of our pres- 
ent knowledge of pre-glacial Lymnezas. 
In Chapter IV an effort has been made to summarize our present 
knowledge concerning the extinct species of American Lymnezas, and 
it is believed that the correlation of the fossil species with those of re- 
cent times will prove of interest. The majority of the fossil species 
are illustrated by the original figures. The list of fossil Lymnzas is 
believed to be fairly exhaustive. Chapter V contains an historical 
sketch of previous monographs. In Chapter VI a new classification 
is proposed, based on the comparative characters of shell, radula and 
genitalia. Many malacologists will not agree with the author in thus 
subdividing this group; in so doing he has only followed the trend of 
modern taxonomy. Chapter VII embraces a consideration of the no- 
menclature. It is believed that the instructions for collecting and pre- 
paring Lymnzas for dry and anatomical study, in Chapter VIII, will 
prove helpful to those having little experience in this subject. 
Chapter IX includes the systematic discussion of the Lymnzas of 
Middle and North America. Each species is discussed under the fol- 
lowing heads: 
Bibliography. 
Description of shells with measurements. 
Location, number, and catalog number of type specimens. 
Type locality. 
Description of Animal. 
Description of Jaw. 
Description of Radula. 
Description of Genitalia. 
Range or Geographical Distribution. 
Records of authentic localities arranged alphabetically by states. 
Geological Range. 
Records of fossil specimens. 
Ecology. 
Remarks. 
