228 DR. CARPENTER'S RESEARCHES ON THE FORAMINIFERA. 



tion afforded by large numbers of specimens, collected (so far as may be possible) 

 from different formations, and from different geographical areas. Until the whole of 

 this process shall have been carefully and systematically gone through, no limitation 

 of a species by a definition of any kind, can be regarded in any other light than as 

 a provisional means of marking-out the existence of a particular type of structure, whose 

 relationship to other types must be a matter of further investigation. 



75. Let me subjoin such "pregnant instances," as shall prove the importance of 

 each of the foregoing principles, from the result of the violation or neglect of it : 

 (1) so long as external conformation was alone regarded, and no account was 

 taken of internal organization, the Nautiloicl Forarninifera were placed among 

 Cephalopods, and the Coralloid forms among Polypifera; to neither of which classes 

 have they any kind of relationship ; (2) so long as developmental history was un- 

 studied, the Hydroid Zoophytes and the Medusoid Acalephse were considered as 

 entirely disconnected groups, belonging to two different Zoological classes, instead 

 of (as in reality) different states of the very same organisms ; (3) so long as reliance 

 is placed on the comparison of a. few individual specimens only, without any account 

 being taken of the intermediate forms by which the more divergent types may be 

 connected, so long are species multiplied to a most unwarrantable excess, as is found 

 to be the case in almost every department of Zoology and Botany by those who 

 devote themselves to a more extended comparison ; thus, nineteen species have been 

 made from the common Potatoe, and many more from the Solanum nigrum ; so, 

 multitudes of species have been instituted in various genera of California!! shells, 

 by the late Mr. C. B. ADAMS, whose identity is established by a more extended 

 comparison of individuals (as will be shown in a Report which is being prepared at 

 the request of the British Association, by my brother, the Rev. P. P. CARPENTER) ; 

 in fact, wherever this test, is conscientiously applied, its effect is to reduce the number 

 of reputed species, sometimes in a most remarkable degree*. (4) In like manner it 

 has been by comparing only a small number of specimens from remote geographical 

 provinces, and by neglecting the intermediate varieties that present themselves even 

 among sufficiently large collections from these, still more among specimens collected 

 from intervening regions, that not only numerous errors of detail have been com- 

 mitted, but general doctrines have been propounded, which the advance of Science 

 has proved to be utterly untenable. As an example of the former kind, may be cited 

 the facts mentioned by Dr. J. D. HOOKER (op. cit.), that of the New Zealand varieties 

 of Oxalis corniculata, one of the most widely-diffused and most variable Flowering 

 plants in the world, no less than seven or eight species have been made, neither of 

 them supposed to be identical with any belonging to the European Flora ; whilst Pteris 



* I am most glad to find my views on this point in accordance with those of Dr. JOSEPH D. HOOKER (see 

 his ' Introductory Essay on the Flora of New Zealand,' 2), who has been led to the conviction, that instead 

 of affirming the existence of 100,000 species of known Plants, we ought not to reckon more than half that 

 number. 



