of Foraminiferal Structure. 167 



precisely in all their characters with those oi Actmophrys "? 

 The fact is that the pseudopodia of no other Ehizopods could 

 possibly present appearances more distinct from each other, 

 both as regards habit and arrangement, than those of these two 

 organisms. 



From what has already been brought forward it will be 

 seen, I think, that the question under discussion, namely the 

 error of making Gromia the tyjDC of foraminiferal structure, is 

 reduced within very narrow limits. In short, it resolves itself 

 into this : — Is the practically imperceptible degree of organiza- 

 tion, which Dr. Carpenter ascribes to the lowest or Reticularian 

 order in his system, exemplified, as he pronounces it to be, in 

 the type Gromia ? Of course, if it be not so exemplified, 

 and if it can be shown, on the one hand, that the so-termed 

 typical pseudopodia of Gromia may be identical in all re- 

 spects with the pseudopodia of the Foraminifera which Dr. 

 Carpenter associates with Gromia, and, on the other hand, 

 that Gromia, the reputed type of extreme primordial sim- 

 plicity, besides having pseudopodia identical with certain 

 Actinophryans, possesses both the nucleus and a contractile 

 vesicle (which Dr. Carpenter allows to be distinctive of the 

 highest degree of physiological development in theHhizopod), 

 there is, of course, on Dr. Carpenter's own showing, an end to 

 his arrangement of these organisms on the basis upon which 

 it has heretofore rested ; and, what is more, there must be 

 an end to every other classification of the Rhizopods which 

 is based, in like manner with his, on characters derived 

 primarily from the pseudopodia. There is no alternative, so 

 far as I can see. And yet, as will presently appear, knowing 

 these facts. Dr. Carpenter is quite unable to brace himself up 

 sufficiently to make the necessary recantation candidly and 

 ungrudgingly. 



In my remarks " On the Distinctive Characters of Amceha " 

 ('Annals,' Aug. 1863) it was mentioned that I had discovered 

 a Avell-marked nucleus in Gromia, but had not, at that time, 

 detected a contractile vesicle. In view, however, of the 

 analogies existing between Gromia and the Amosbce, so con- 

 fident was I that the organ was there, that I expressed my 

 conviction that I should speedily be able to trace the con- 

 tractile vesicle also, adding that, if traced, the transfer of 

 Gromia from the lowest to the highest order would of course be 

 inevitable. Having for many months, both before and after- 

 wards, spent many hours daily in watching the changes taking 

 place in specimens of various genera of E,hizopods kept in 

 tanks, I was fortunate enough in November of the same year 

 to see the long-looked-for contractile vesicle in Gromia. This 



