124 Bibliographical Notice. 
proved inadequate to the requirements of systematists. The great 
increase in the number of known species, and the numerous new 
types which have been discovered of recent years, together with the 
increased knowledge of the anatomy of a large number of forms, 
have rendered those old classifications more or less obsolete. The 
volume before us will therefore be most acceptable to conchologists, 
for it not only furnishes us with an up-to-date classification, but 
one which is based upon an extensive study of the soft parts, besides 
those ordinal characters which may be found in the shells also. 
This system is not founded upon the modifications of a single organ, 
such as the Jaw, the radula, or the shell, but all the organs of the 
animal, internal and external, have been taken into account with 
very gratifying results. .The author has not only taken advantage 
of the anatomical researches of others, but himself has prepared 
more than five hundred dissections. 
The two families Endodontide and Helicide are treated of in this 
volume. The former is divided into two tribes or sections—Poly- 
placognatha and Haplogona—respectively containing two and five 
genera. Five sections are suggested for the Helicide, namely, 
Protogona, Macrogona, Teleophallogona, Epiphallogona, and Belo- 
gona, and these contain as many as fifty-two genera. Besides these, 
four other genera of doubtful affinities are included in this family. 
A synopsis of all the genera of these two families is followed by two 
keys to them, one derived from anatomical, the other from shell 
characters. The remainder of the forty-eight introductory pages 
of this volume contain remarks on the distribution of Helices in 
time and space, instructions with regard to the preparation of land- 
snails for anatomical study, and a short note on nomenclature. 
The bulk of the volume consists of detailed descriptions of the 
various genera, an account of their mutual relationship, the facts in 
connexion with their geographical distribution, and, finally, what 
will be most useful and valued by the collector, a list of the species 
included in each genus. The pictorial portion of the work consists 
of 71 plates, containing 561 figures of shells and 571 illustrating 
the anatomy ; and of these 330 were drawn by the author. 
From our own experience, and from the opinions expressed by 
practical conchologists, we can speak with much confidence of the 
great merit and usefulness of this work; and Mr. Pilsbry is to be 
congratulated upon the completion of a book entailing such a vast 
amount of research and containing a classification of such an enor- 
mous group as the Helices, which will be indispensable to the 
student of land Mollusca, and, indeed, will form for many years to 
come the standard work upon the subject treated of. 
In conclusion, we would express the hope that Mr. Pilsbry may 
be induced to undertake a companion volume on the Zonitide and 
Agnatha, which is hinted at in his prefatory remarks. 
