the Distinctive Characters in Amoeba. 125 



until I have enjoyed further opportunities of studying the bodies 

 in question. 



On the mode of development of the nucleated corpuscles 

 and sarcoblasts of Amoeba, I have nothing to add to my pre- 

 vious observations ; but I may avail myself of the opportunity 

 to state that, in the earliest recognizable condition in which 

 I have found Polycystina and Acanthoraetrina occurring as 

 independent free-floating organisms at the surface of tropical 

 seas, their rudimentary shell or framework* has invariably been 

 enveloped in bodies precisely resembling the sarcoblasts of the 

 mature forms. Since every gradation in size of these organisms 

 has been met with by me, from that most minute condition in 

 which they are scarcely larger than the large sarcoblasts found 

 within the parent forms, to the fully-grown individuals, — and 

 since the sarcoblasts of Thalassicolla have been met with by me 

 in abundance, occurring both within and without the nuclear 

 capsule, within and without the shell or spicular representatives 

 of the shell in the form in which the latter are present, there 

 can be no doubt, I think, that to this extent I have traced their 

 share in the reproductive process. But whether any true repro- 

 ductive act precedes their appearance or maturation, I have no 

 evidence whatever to show ; nor ought any evidence to be ac- 

 cepted as proof until the unbroken chain of attendant pheno- 

 mena shall have been consecutively seen and described. 



I may here mention that, as pointed out in Amoeba, the nu- 

 cleated corpuscles as well as the sarcoblasts have been detected 

 by me in the Foraminifera, the Polycystina, the Acanthodesmidse, 

 Acanthometrina, ThalassicoUidse, and Dictyochidse — all pelagic 

 forms. In the Foraminifera the primordial segment is in reality 

 the homologue of the omphalostype ; and it seems by no means 

 improbable that the coccospheres, already alluded to as consti- 

 tuting a phase in the development of some of the genera (as, for 

 example, Textvlaria), may prove to be an advanced stage of their 

 sarcoblasts. I have never seen a coccosphere within the chamber 

 of a Foraminifer; but I may state that I possess numerous spe- 

 cimens of these bodies (from the single primordial chamber to 

 the perfectly formed multiple segments of the shell) in which 

 each chamber has retained the characters of the coccosphere to 

 the last. 



The first portion of the Amoeban structure to which Mr. Carter 

 draws attention he terms " the pellicula,^^ stating that " inference 

 leads us to the conclusion that there is a pellicle over the surface 

 of A. princeps, however thin ; and the fact that very frequently, 



* As the earliest rudiment of the hard shell or framework of these 

 organisms furnishes a most important character in their classification, I 

 have applied to them the term omphalostypes . 



