37 



represents in his mind. Without such expression it is safe to suppose 

 that no such idea exists ; and if so, the name should be regarded as a cipher 

 in the literature of science. 



That certainty as to the limits and hence definition of a genus is not 

 at once attainable, is no objection to the above rule. By study of known 

 forms definite knowledge of generic characters may be attained by 

 proper analysis. But whether correct or not, a generic description 

 expresses something definite, and gives the name a currency which 

 should remain as a record of honest work. 



The evils which come from the opposite course are numerous. They 

 are : 1st. Names without description are unintelligible, and communicate 

 nothing. 3d. They serve to conceal the ignorance or incompetency of 

 their authors. 3d. If allowed, they open the door to the introduction of 

 names on geographical and stratigraphical grounds ; a slovenly pratice, 

 indulged in by a few paleontologists, and properly denounced by Fal- 

 coner, as assuming at the outset what it is the design of the science to 

 prove. The same practice attempted in zoology has been utterly con- 

 demned, as for example in the case of the System Reptilium, published in 

 1843. Here pages of generic names may be found, with type species indi- 

 cated, which have no authority whatever. 4th. The practice lays the 

 science open to the inroads of charlatans and scientific pirates, who seek 

 to impose a nomenclature without the labor of discovering a system or 

 describing its objects. 5th. As the genus is a more important conception 

 in palseontological science than the species, it is more important that what 

 its name represents should be clearly understood, otherwise generaliza- 

 tions become impossible or incomprehensible. 



(4.) When a supposed genus is found to consist of several, and the 

 author has stated what he regards as the type of the former, that 

 species must retain the original name. Where the type of the original 

 genus is unknown, the original name must attach to that genus which 

 remains, after subtraction of the others found to be embraced in the 

 original assemblage. 



Note. This rule is adopted as doing less violence to long accepted views 

 and practice in nomenclature than any other. While recognizing the 

 work of the original author, it also preserves record of the labor of those 

 who have determined the true divisions with more exactitude. 



EXPLANATION OF PLATES. 



PI. 1. LoxolopJwdon cornutus, Cope, profile natural size. 

 PI. 2. The same from the front. 

 PI. 3. Superior view of the same. 



PI. 4. Inferior view. 

 Published March 14th, 1873. 



