APPENDIX D. xciii 



insensible gradations with the Foraminifera, in which the 

 shells have many chambers. Speaking of these creatures, 

 Dr. Carpenter says 1 : 'The range of variation is so great 

 among Foraminifera, as to include not merely the differential 

 characters which systematists, proceeding upon the ordinary 

 methods, have accounted specific, but also those upon which 

 the greater part of the genera of this group have been founded, 

 and even in some instances those of its orders. . . . The 

 ordinary notion of species, as assemblages of individuals 

 marked out from each other by definite characters that have 

 been genetically transmitted from original prototypes simi- 

 larly distinguished, is quite inapplicable to this group ; since 

 even if the limits of such assemblages were extended so as 

 to include what would elsewhere be accounted genera, they 

 would still be found so intimately connected by grada- 

 tional links, that definite lines of demarcation could not be 

 drawn between them. . . . The only natural classification 

 of the vast aggregate of diversified forms which this group 

 contains, will be one which ranges them according to their 

 direction and degree of divergence from a small number of 

 principal family types/ 



Between Amcebce and the Actinophryna, again, there are 

 the closest affinities. On this subject Nicolet says : ' In its 

 different modes of development the Amceba often assumes 

 the radiated form of the Actinophrys, and this so exactly, 

 that the greatest attention is needed to distinguish the one 

 from the other; also all the authors who have concerned 

 themselves with the classification of these Microzoa, and 

 with the determination of their generic forms, have always 

 confounded the radiated Amoeba with the Actinophrys pro- 

 perly so called. It will suffice to mention Actinophrys 



1 Introduction to ' Study of Foraminifera' (Ray Society), 1862, p. x. 



