6 Trans. Acad. Set. of St. Louis. 



agonal. In Fig. 12 a the third column begins with a hexag- 

 agonal plate and in Fig. 4 a the first column introduced begins 

 with a hexagonal plate. 



Then, again, the initial plate of a column when pentagonal 

 often has the apex pointing dorsally, and I am unable to 

 understand how this feature can be " an important aid in diag- 

 nosing the relative position of the axes in even fragmentary 

 specimens," as claimed by Jackson and Jaggar.* Having a 

 piece of perhaps only a dozen plates, it is impossible to de- 

 termine anything at all about it — such a specimen having no 

 value in the determination of characteristics. The only thing 

 which can fix the relative position of the axes positively is the 

 presence of the apical disk or the masticatory apparatus, or, 

 at least, of the space once occupied by those organs. 



It is to be regretted that scientists are ever ready to create 

 new species from mere fragments, or because a specimen 

 shows an additional column, or because the individual plates 

 are larger or smaller than usual. All these features are of 

 only secondary importance and should never be considered of 

 generic or even specific value. Any feature to be truly of 

 importance in determining species must be constant and 

 typical in all specimens belonging to that species. The great- 

 est care should be exercised in basing new genera or even new 

 species on a single specimen or a fragment. Palaeontologists 

 very often, in their eagerness to describe their specimens, 

 cause a great deal of confusion by creating new species and 

 burden the literature with many synonyms, which it may take 

 years and the labor of a number of scientists to eradicate. 

 So Mr. Beede in describing his Oligoporus ? minutus says: f 

 " It will in all probability be found to belong to an entirely 

 different genus. It is referred to Oligoporus for convenience, 

 until better material can be secured." Since the author feels 

 almost sure that the specimen does not belong to that genus, 

 why burden the science with a meaningless name instead of 

 waiting for better material and then describing and placing 

 the fossil in its proper place? So Mr. Keyes adds to the list 



* Bull. Geol. Soc. Amer., vol. 7, p. 149. 



f Kansas University Quarterly, Series A, vol. 8, no. 3, p. 126. 



