458 ORIGINAL ARTICLES. 



seems to me) on a truer perception of the value of characters than 

 most of the classifications that have been since proposed. For Dujardin 

 distinctly recognized the fact that Arcella and Difflugia are nothing 

 else than testaceous Amoebans ; and in separating these from those 

 Bliizopods which are characterized by the possession of filiform, 

 tapering, or ramifying pseudopodia, he laid the foundation of a truly 

 natural grouping of the latter. Had he recognized the fact that his 

 group of (testaceous) Eliizopods is related, on the one side, not less 

 closely to Actinoplirys than it is, on the other, to Amoeba, and that 

 Trinema and Euglyplia are really formed on the Actinophryan type, 

 whilst Gromia is the representative of the Foraminiferous, he would 

 have marked out, upon a sound basis, what appear to me to be the 

 fundamental divisions of the class. Even in separating Miliola from 

 the ordinary Foraminifera, he adopted a principle which I believe to 

 be perfectly correct, though his limited acquaintance with the group 

 misled him in the application of it; for, as I shall hereafter show, 

 Miliola is the type of a large group of Foraminifera in which the 

 body is inclosed by an imperforate shell, so that there is no exit for 

 its pseudopodial extensions except by the apertural plane, in which 

 there is sometimes (as in Miliola) a single large orifice, whilst in 

 other cases it is replaced by a multiplicity of distinct pores. The 

 differentiation between this group and the one in which the shell, 

 being everywhere perforated with pores more or less fine, allows the 

 passage of pseudopodia from every part of the surface,, of the body, 

 I hold, with Dujardin, to be of essential importance. 



These considerations have been altogether passed over, not only by 

 M. D'Orbigny, who adopted Dujardin's rectification of the position 

 of the Foraminifera in the zoological series, without in any way modi- 

 fying the classification of the group which he had previously devised 

 under the notion that the animals by which these shells are formed 

 are minute Cephalopods, but also by Prof. Schultze, who, having 

 applied himself to the study of the Foraminifera and their allies in 

 the living condition, might be expected to have gained more insight 

 into their true relations as indicated by the characters furnished by 

 their sarcode-bodies. Tet he shows himself to be so completely under 

 the influence of views of systematization based on the characters of 

 the shell, and to have so little regard even to the most important 

 structural and physiological differences anywhere presented by the 

 animals of this class, as to associate in his family Lagynidce* — for no 

 other reason than that they agree in the possession of a unilocular 

 test, Arcella and Difflugia — whose animals are of the Arnoeban type, 

 Trinema and Euglypha — whose animals are Actinophryan in cha- 

 racter, Gromia — whose animal is the type of that of the imperforate- 

 shelled Foraminifera, Squamulina — which has an imperforate cal- 

 careous shell of the Milioline type, and Ovulina — whose shell is 



* See his treatise, " Ueber den Organismus der Polytlialamien (Foraminiferen) 

 nebst Bermerkungen liber die Rhizopoden in allgemeinen." Leipzig, 1854. 



