932 The American Naturalist. [November, 
(c) When the two sexes of the same species have been con- 
sidered as distinct species or as belonging to different genera. 
(d) When the animal presents a regular succession of unlike 
generations, which have been considered as belonging to divers 
species or even genera. 
17. It is very desirable that each new description of a genus 
or species be accompanied by a diagnosis in Latin, or, at least, 
a diagnosis in one of the four best known European languages, 
i. e., French, English, German, Italian. 
18. In works not published in one of the above-mentioned 
languages, the explanation of the plates should be translated 
entire, either into Latin or one of the continental languages. 
19. When several names have been proposed simultaneously, 
and priority for any one cannot be established, there should 
be adopted— 
(a) That name which is applied to a well-characterized and 
typical species, in case of a generic name. 
(b) That name which is accompanied by either figure, 
diagnosis or description of an adult form, in case of a specific 
name. 
20. Generic names already employed in the same kingdom 
cannot be used. 
21. The use of those names should be avoided which can 
only be distinguished by their gender endings or by a simple 
orthographic change. 
22. Specific names already employed in the name genus 
cannot be used. 
23. The generic and specific names which become non-avail- 
able through the application of the foregoing rules cannot be 
employed anew, even if they express a new meaning in the 
same kingdom, if the name is generic; in the same genus if 
the name is specific. 
24. A generic or specific name once published cannot be 
withdrawn, even by its author, on account of ambiguity. 
25. All barbarisms and solecisms must be corrected; hybrid 
names, however, such as Geovula, Vermipsylla should be re- 
ined. 
