322 Dr. Wallich on the RMzopods. 



Under the head of characters relating to the Proteiua it was 

 further stated that the presence of two such organs as the 

 nucleus and contractile vesicle must be regarded as of primary 

 importance, reasons having already been assigned for con- 

 sidering the degree of differentiation of the sarcodic body 

 alleged to be deducible from the shape, form, proportions, and 

 arrangement of the pseudopodia as of merely secondary value ; 

 and that, after a laborious study of the freshwater Proteina 

 extending over nearly two years, without any important inter- 

 mission, I felt satisfied that, even if made the basis of generic 

 subdivision, these pseudopodian characters " are subject to a 

 much wider range of variation than is usually imagined," not 

 only in the same genus, but in the same individual at diffe- 

 rent periods of its existence " *. 



It was during the above-mentioned continuous study of the 

 Proteina that I verified the fact of the presence of a contrac- 

 tile vesicle in Gromia in a sufficiently large number of cases 

 to place the matter beyond doubt. This was mentioned in 

 a paper " On the Fundamental Error of constituting Gromia 

 the Type of Foraminiferal Structure," published in the 

 'Annals' for Feb. 1877, p. 168. 



Meanwhile, however. Dr. Carpenter had brought out the 

 fifth edition of his most excellent treatise on ' The Microscope,' 

 and had so far modified his views as to insert the following 

 remark respecting the characters upon which he still depended 

 for the subdivision of the Rhizopods into orders : — " It must be 

 freely admitted," he said, " that these groups [the Eeticularia, 

 Eadiolaria, and Lobosa] cannot be distinctly marked out, the 

 typical examples which will now be described being connected 

 by many intermediate forms. This is not to be wondered at 

 when the extreme indefiniteness which characterizes the 



lowest type of animal life is duly borne in mind In 



Gromia, moreover, we have an example of a Rhizopod which 

 very characteristically exhibits the Reticularian type in the 

 disposition of the pseudopodia, but which Dr. Wallich was 

 the first to point out possesses both a nucleus and contractile 

 vesicle, thus showing a transition to the higher orders^ — Op. 

 cit. pp. 168, 169. 



It needs no argument of mine to prove that a more illo- 

 gical and hazardous conclusion could not have been drawn 

 from so very significant a fact, for, instead of the altered 

 position of Oromia being in anywise accounted for by at- 



* For details of the grounds on -wliicli T rested my statements con- 

 cerning the worthlessness of ordinal and generic characters derived from 

 the pseudopodia see papers on the Ehizopods in the ' Annals ' for Nov. 

 1863 and Dec. 1868. 



