184 
MONOGRAPH OF THE GENES STROPHIA. 
In studying Strophia, I have always endeavored to first thoroughly 
understand the intricacies of the oscillations of individual variation, 
— greater in some species than in others — then have indicated the 
more or less set forms that have passed beyond mere individual varia- 
tion, but which have not lost the links that bind them to the parent 
stock; thus have been prepared to recognize species, even if closely al- 
lied, wherein there are no true connecting links. 
In concluding this digression, which I have considered necessary 
to make at this time, I shall recapitulate somewhat in the following re- 
marks, in order to emphasize some of my assertions. 
The genus Strophia is larger and much more important than has 
been supposed. On this side of the Atlantic, at least, it has been much 
neglected, and consequently many collections are in a sad state of confu- 
sion regarding proper names being appended to species. Many easily 
recognized species have received the same name, and the same species 
sometimes bear different names in the same collection, (in one instance 
two lots of one species labelled as coming from one locality, have received 
different names, both of which are in the same handwriting ! ) while in 
many cases the same species bears different names in different collec- 
tions. Much of this confusion is due to the fact that, with a few ex- 
ceptions, writers upon Strophia, especially the older authors, have not 
given enough attention to details, hence one description often embra- 
ces more than one species. They have scarcely ever recognized the 
importance of isolation as indicating species, and are thus apt to assign 
too wide a range to one species. 
Many students of today in endeavoring to identify species by these 
descriptions have tried to make too few names fit too many species, and 
through an unfamiliarity with the subject have not observed their error. 
Indvidual variation is sometimes comparatively great in species of 
Strophia, yet this has its limits, becoming overbalanced into forms, and 
these, in turn, into species. A tendency to indicate the species that has 
been evolved through the isolation of individuals, by a greater or less 
prominence of some particular character, on one hand, and reversion 
in some specimens of that recently evolved species, will sometimes 
form what are apparently connecting links between the two species. 
Such apparent links are, however, always represented by a very small 
percentage of specimens, and a close study of them, will, in all cases, 
show to which species each belongs. Strophia, to be understood, requires 
careful study and attention, more so than most genera of shells, but 
when once mastered, certain characters that before seemed obscure, now 
become perfectly clear. 
