70 INVERTEBRATE PALAEONTOLOGY 



the genotype of Pygaster by Agassiz. By a series of 

 errors and misconceptions, the specific name came to be 

 applied to an allied, but quite distinct, form common 

 in the Inferior Oolite of Gloucestershire. From 1857 

 onwards this Lower Oolitic Echinoid was always called 

 Pygaster semisulcatus, the misapplication of the specific 

 term being stereotyped in Wright's monograph. Later 

 writers habitually referred to Pygaster semisulcatus 

 ("Phillips") when dealing with the Inferior Oolite 

 form, when, as subsequent research has proved, the 

 species meant was " P. semisulcatus, Wright (non 

 Phillips)." Had their references been made in the 

 latter way, much confusion would have been pre- 

 vented, since P. semisulcatus (Phillips, non Wright) 

 is an entirely different species, and occurs in the 

 Corallian only. 



Since confident identification of species demands long 

 study, and often special knowledge of the groups con- 

 cerned, it is practically impossible for a stratigrapher to 

 definitely and correctly name many of the varied forms 

 that he collects. Unless the help of " specialists " in the 

 different groups can be obtained, it is safer, and less 

 misleading, to compare fossils with described types 

 rather than to identify them. Especially since true 

 identity between any two specimens is well-nigh in- 

 conceivable, a list of fossils which includes absolute 

 specific determinations is less convincing than one in 

 which the fossils are said to be comparable with species 

 previously diagnosed. Greater experience, and more 

 material, always tend to lessen the confidence with 

 which specific names are applied ; it is not furthering 

 the cause of Science if Stratigraphers rush in where 

 Palaeontologists fear to tread ! 



The foregoing comments apply to original work ; 

 their rigid adoption would make pedagogic palaeon- 



