326 Dr. Wallicli on the Rhizopods. 



suffered any inconvenience. And it happens just as com- 

 monly that an ordinary naked Amoeba will, whilst under ob- 

 servation, take summary possession of the first empty Difflugian 

 or Arcellian test that comes in its way, and at once make 

 itself quite at home in its new quarters ; the newly-assumed 

 characters being in each instance so perfectly sustained as to 

 leave an observer who has not actually witnessed the trans- 

 formation no reason to suspect the now testaceous form to have 

 ever been otherwise than testaceous, or the now naked form 

 otherwise than naked. 



Other analogies and identities of procedure might be cited, 

 as, for example, those connected with the process termed 

 zygosis, of which nothing is in reality known, though several 

 hypothetical explanations have been hazarded on the subject. 

 So far, then, we encounter no anomaly ; but should we push 

 our investigations a step or two further we find ourselves con- 

 fronted by what at first seems to be not only an unrecognized 

 anomaly, but a paradox. And here Gromia retaliates on 

 those who once degraded it, not only by refusing to throw 

 any light on the difficulty, but by doing its best to lend force 

 to it. Formerly, as we now are aware, Gromia was wrongly 

 held to be the type of " the very simplest form of Foramini- 

 fer," by virtue of the so-termed Reticularian type of its pseudo- 

 podia. Yet in recognition of its possessing a nucleus and 

 contractile vesicle, it has been promoted to the highest status 

 in the Rhizopod scale. Its test is one of the simplest to be 

 met with in the highest order, and, when it stood side by 

 side with the simplest Biloculine Miliolidfe in the lowest 

 order, was firmly believed to be just as simple in organi- 

 zation as they. But we have it on the authority of Dr. 

 Carpenter, who probably knows more than any other man 

 living of the structure and " plan of growth " of the shells of 

 the Foraminifera (and any one who has under his guidance 

 studied these exquisitely formed structures must have arrived 

 at the same conclusion), that the Foraminifera, which stand 

 at the very bottom of the Rhizopodal series in point of bodily 

 organization, possess " shells which are unsurpassed in sym- 

 metry and complexity of structure hy any testaceous or- 

 ganisms "*. 



On the other hand, we see in the highest order of the 

 Rhizopods the animal of Difflugia and its now firmly esta- 

 blished compeer (as regards complexity of bodily organization) 

 both in possession of protective coverings, the extreme simpli- 

 city of which is " unsurpassed by that of any other organisms !" 



* ' The Study of the Foramiuitera,' by Dr. Carpenter, F.K.S.; 18G2, 

 Preface, p. viii. 



