No. 570] TAXONOMY AND EVOLUTION. 



376 



genera, systematists have sometimes dropped into some curious 

 errors. Teratologic^ specimens have been described as new 

 species and most zoologists have heard of the man who de- 

 scribed as a new species the longicorn beetle, the head of which 

 having fallen oft', had been fixed on upside down. His examina- 

 tion of a new species makes so slight an impression on his mind 

 that sometimes the same worker has described the same form 

 twice under different names. 



The descriptive papers on Mollusca usually consist of short 

 descriptions of the shells, even written in a dead language. This 

 is conchology. Conchologi'sts confine themselves to the pat- 

 terns and shapes of shells — nature's medallions — numismatics! 

 Much of this work — along with similar productions in entomol- 

 ogy and carcinology — we regard as positively flagitious. 



Sir Ray Lankester in the article "Zoology" in the Encyclo- 

 paedia Britannica (ed. XI.) remarks that museum naturalists 

 must give attention to the inside as well as to the outside of 

 animals and that to-day no one considers a study of an animal's 

 form of any value which does not include internal structure, 

 histology and embryology in its scope. Agassiz, too in his 

 famous ''Essay on classification" wrote that "the mere indi- 

 cation of a species is a poor addition to onr knowledge when 

 compared with such monographs as Lyonnet's Cossus, Bojanus' 

 'Turtle' Strauss Durckheiims M<lo!ontha and Owen's Nauti- 

 lus." 



"But," it will immediately be asked in chorus, "do you 

 seriously suggest that a monographic volume should be devoted 

 to every new species?" 



This is a leading question which brings us to the crux of the 

 whole matter, and can not be answered in simple "Yea" or 

 "Nay." 



The Provisional Diagnosis 

 The amount of analytical study that may be given to any one 

 animal form in any one stage of its development is infinite. 

 The result is that in describing a new species for the purposes 

 of exact phylogenetie classification there must be a limit beyond 

 which it is unnecessary to go. Such a limit can not be otherwise 

 than arbitrarily selected according to the best judgment of the 

 systematic worker as to how much analysis is required to place 

 his new species, although at present, miserabih dictu, relatively 



