378 
ME, W. K. PAEKEE AMD PEOPESSOE T. E. JONES ON SOME 
Genus Planorbulina. 
Planorbulina farcta, Fichtel and Moll, sp. (Varieties). Plate XIV. figs. 3-11 (Arctic); 
Plate XVI. figs. 18-25 (North Atlantic). 
This is a very common variety of a species belonging to the Rotaline group of Fora- 
minifera. In endeavouring to elucidate the relationships of the Botalince, we have been 
impressed with the distinctiveness of nine specific groups, six of which have more or less 
of the well-known Potalian shape, and are extremely rich in varietal forms (see Dr. 
Carpenter’s ‘ Introd. Study Foram.’ Ray Soc. 1862, pp. 198, &c.). A great proportion 
of these varieties have been described by authors under the generic term “ Rotalia”; 
others have been grouped under the leading names of Bosalina, Planorbulina , Gyroidina, 
Anomalina , Tru/ncatulina , and several others, supposed to be of subgeneric, or even of 
generic, value. An artificial classification and extreme confusion have been the conse- 
quence. After a long examination of the subject in its bibliographic aspect, and having 
carefully studied large numbers of the actual organisms, recent and fossil, we find that 
they range themselves around six specific centres, which may also be regarded as types 
of so many genera ; and with these are allied three other specific forms, not so Rotalian 
in aspect ( Tinojoorus , Patellina, and Polytrema). 
The protean variability of all the six Rotalian types being great, and isomorphism, or 
similarity of form among the varieties and subvarieties of these several specific groups, 
being of very frequent occurrence, we still use binomial terms, in a subgeneric sense, for 
members of this great group ; and often, in ordinary descriptions, we retain, for the sake 
of convenience, binomial appellations (without direct reference to their exact zoological 
value) for striking specimens even of varieties and subvarieties. Thus Tru/ncatulina 
lobatula is a distinct binomial term for the common variety of Planorbulina farcta first 
to be noticed (page 381). 
The old name Botalia is retained for one of these six genera; and we arrange the 
whole as a subfamily with the appellation of Rotalinae*. 
Discorbina Turbo, D'Orb., sp. 
Planorbulina farcta, Fichtel and Moll , sp. 
Pulvinulina repanda, Fichtel and Moll , sp. 
Rotalia Beccarii, Linn ., sp. 
Cymbalopora Poyei, D'Orb.. sp. 
Calcarina Spengleri, Gmelin , sp. 
Tinoporus laevis, Parker and Jones , sp. 
Patellina concava, Lam., sp. 
Polytrema miniaceum, Esper, sp. 
Each of the six Rotaliform genera is represented by one typical species, which carries 
with it a large number (from 50 to 200 or 300) of divergent forms, most of them having 
* See Carpenter's £ Introd. Eoram.’ Ray Soc. 1862, pp. 198, Ac. 
