12 CARBONIFEROUS AND PERMIAN FORAMINIFERA. 



indicate that they represent assemblages of individuals of the same zoological distinctness 

 collectively. Most of the generic terms which have come into general use have been 

 applied to groups of Foraminifera more or less circumscribed, though often overlapping 

 other similar groups in a way to render complete separation impossible ; but to reject 

 them entirely because they do not fulfil conditions that might properly now be exacted, 

 would throw the whole nomenclature into confusion by necessitating the alteration of 

 very many " specific " names. No harm is done by the employment of these quasi-generic 

 terms so long as their significance is understood, though their acceptance is a com- 

 promise dictated by convenience. For similar reasons it seems best to avoid as far as 

 possible the trinomial use of " varietal " names when the relationship of the subordinate 

 forms has once been sufficiently indicated.- But after making every allowance, and 

 admitting the title of even slight modification of characters to recognition by a distinctive 

 name, there are still enormous numbers of so-called " species " that are absolutely 

 synonymous, and right of precedence once determined, the more completely the remainder 

 are cleared away the better for scientific terminology. 



It seems strange to have to insist on zoological characters as the only right foundation 

 for species ; but to judge by the sort of criticism which the results of the purely zoological 

 treatment of fossil Foraminifera by my colleagues and myself in past years have called 

 forth in some continental publications, one might suppose that it was an almost unheard- 

 of proposition. The practice of re-naming organisms, zoologically identical, every time 

 they present themselves at a fresh geological horizon is still largely adopted, on the 

 ground that in the absence of any evidence of continuity a new creation must be 

 assumed, and that a new specific name becomes a necessary consequence, conclusions alike 

 untenable. It would be just as reasonable to found such an argument on geographical 

 as on geological conditions. Widely different geological age may be admitted to have 

 some weight in doubtful cases, but only as an addition to zoological evidence, not in con- 

 tradiction to it. 



These preliminary observations lead to questions more directly affecting the Carboni- 

 ferous and Permian fauna ; and in reviewing its general aspect and relations we shall find 

 it convenient to take the larger groups of the English classification seriatim, and pretty 

 much in the order in which they appear in the foregoing table. In following this course, 

 however, I must guard against the supposition that this, or indeed any classification as 

 yet proposed, accords quite satisfactorily with the existing state of our knowledge, though 

 it may answer our present purpose as well as a more elaborate scheme. 



Commencing with the Imperforaia : the family Gromida may be dismissed in a 

 word, without even questioning its right to the position it occupies, inasmuch as no 

 fossil Rhizopoda with chitinous tests have hitherto been recorded, and the very 

 nature of their investment renders their discovery improbable. The Miliolida may be 

 passed over almost in like manner, for no porcellanous forms have been met with in deposits 



