16 BUREAU OF ANIMAL INDUSTRY. 



LII. When an author has specified no type, it is then necessary in dividing his 

 genus to retain his name for the subdivision containing the species which the next 

 subsequent author treating of the genus has specified or regarded as the typical 

 exemplar. (B. A.) If no subsequent author has selected a type, the first species 

 of the primitive author may frequently be taken a* the type, or a species may be 

 selected from among those originally specified as belonging to the genus when it was 

 formed, due regard being paid to the necessity of retaining as many of the original 

 species as possible in the division which is to retain the old name. 



It would manifestly l>e liable to introduce errors and confusion if it were insisted 

 that the first species should invariably be taken as the type, or were it permitted to 

 take species subsequently added to the group, and which the original author did not 

 know when he established his genus. No arbitrary rule will suffice to determine 

 offhand questions of so much complication as is often the decision in regard to the 

 type of an ancient genus which has been studied by a number of authors. 



In the first of the above cases lists are often arranged in alphabetical or faunistic 

 order, or the aberrant species are placed at or near the beginning and end of the list, 

 while the more generalized and characteristic species are put between the others. 

 In the second case, aberrant species might be added and subsequently taken away 

 from the genus, carrying with them the name consecrated by the primitive author 

 to the very group which the subsequent reviser might then seize on for his own. 

 Still more, the aberrant species carrying the primitive generic; name might subse- 

 quently be found to belong to a genus described before the one revised. Then the 

 name originally given to a valid group might be subject to rejection as a synonym, 

 " while the valid group itself which originally bore that name was rejoicing under a 

 new appellation received from the industrious revisers! Absurd as it may appear, 

 mutations similar to this might be mentioned. 



The answers received to questions on this point in the circular will be seen to be 

 by a large majority in concurrence with this section. 



LIII. In dividing a genus of which there are already synonyms, if these syno- 

 nyms or any of them are typified by the same species or group of species as that or 

 those originally selected as types for the primitive genus, the names should be can- 

 celed in toto and not used for the restricted subdivisions. (B. A.) 



To use strictly equivalent synonyms in a new sense for different divisions in one 

 family is sure to create confusion and necessitate lengthy discriminating passages in 

 subsequent synonymical work. When the so-called synonyms are founded' on spe- 

 cies belonging to different sections of the genus, although the names may have been 

 considered as coextensive in their application, it is desirable to use these names to 

 indicate the divisions of the genus when it may be revised. (B. A.) In fact there 

 is hardly any difference between the latter case and the revival of a valid but for- 

 gotten name for the group properly designated by it and to which another legal 

 name can not be applied. 



LIV. In the case of the consolidation of two or more groups of the same nature, 

 .the oldest name must be retained for the whole. If both or all are of the same date, 

 the reviser may select the one to be retained. (B. A., D. 0. ) 



If a name of a genus be so defined as to be equal in extent to two or more pre- 

 viously published genera, it must be canceled in toto. (B. A. ) Example: Tritonmm 

 Miiller was so defined as to be equal to Buccinum, Strombus, and Murex of Linnseus. 

 Hence it should be wholly rejected. Psaracolius Wagler is equivalent to five or six 

 previously published genera, and must, therefore, be canceled. (B. A.) 



It follows from the above that when it is necessary to unite several groups already 

 named the earliest unobjectionable name must be retained for the consolidated 

 group, with a modified diagnosis. 



