MUSEUM OF COMPARATIVE ZOOLOGY. 249 



somewhat approach them, and the name retained. In other cases 

 the species i- retained without its character being questioned, the name 

 and the original description being copied by succeeding writers, till the 

 species becomes traditionally accepted without its claims to recognition 

 having been critically examined. 



Another noteworthy coincidence in regard to nominal species is the 

 fact of their most frequent occurrence in obscurely known groups, which 

 obscurity usually results from the difficulty of obtaining specimens of 

 the forms in question, — either from the remoteness of their habitat, 

 their scarcity, or the peculiarities of their habits, — or from preconceived 

 notions of the intimate relationship of the species of such groups. 



Since the above was put in type. I have for the first time met with 

 some important and timely remarks by an eminent English botanist 

 concerning variation within specific limits in plants, which are so 

 apropos to what has been said above in regard to individual and 

 climatic variation in birds, and contains, moreover, such judicious 

 strictures on various practices indulged in by botanist-, and of which 

 zoologists are equally guilty, that a short abstract of them forms a fit- 

 ting conclusion to the present paper. Says Dr. J. D. Hooker, in the 

 introductory essay to his " Flora Nova>Zelandia3 " (Part I, pp. xii, xiii, 

 xv, 1853) : — - 



" Some naturalists consider every minute character, if only tolerably 

 constant or even prevalent, as of specific value ; they consider two or 

 more doubtful species to be distinct till they have been proved to be one ; 

 they limit the ranges of distribution, and regard plants from widely severed 

 localities as almost necessarily distinct ; they do not allow for the effects 

 of local peculiarities in temperature, humidity, soil, or exposure, except 

 they can absolutely trace the cause to the effect ; and they hence attach 

 great importance to habit, stature, color, hairiness, period of flowering, etc. 

 These views, whether acknowledged or not, are practically carried out in 

 many of the local floras of Europe, and by some of the most acute ami ob- 

 servant botanists of the day; and it is difficult to overestimate the amount 

 of synonomy and confusion which they have introduced into some of the 

 commonest and most variable of plants J n working up incom- 

 plete floras especially,! believe it to be of the utmost importance to regard 

 dubious species as varieties, to take enlarged views of the range i f 

 variation in species, and to weigh characters not only per sc\ but with 



