and other Indigenous Rhizopods. 445 



tion was derivable from their distribution. The contractile 

 vesicles were multiple also, two being distinctly visible, and in 

 regular rhythmical action along the peripheral plane of each half; 

 whilst others may have been present, but obscured on the upper 

 or under surfaces of the structure. When first seen, the well- 

 marked peripheral layer of protoplasmic cellules belonging to 

 each half was uninterrupted at the constricted portion; and 

 around the latter was a somewhat irregular zone of bubble-like 

 protoplasm, which merged into that of the masses on either side 

 of it. But soon the constriction became more and more com- 

 plete ; and after a time the two halves were held together only 

 by a nai*row isthmus of sarcode. At this stage, however, a re- 

 trogressive action commenced, and ultimately the two portions 

 became fused into a single Actinophrys. No movement was 

 observable except on the systole of the contractile vesicles, when 

 the half on which the vesicle was situated oscillated slightly, but 

 very perceptibly. I have only to add that no other specimen was 

 placed on the watch-glass during these appearances, which lasted 

 over a period of four hours. The single specimen then measured 

 ^th of an inch in diameter independently of the pseudopodia. 



These examples are instructive for two reasons : firstly, be- 

 cause they tend directly to confirm the statement originally put 

 forward by Schneider with reference to the occasional zygosis or 

 coalescence of two previously distinct individuals; and secondly, 

 because they indicate how much caution ought to be exercised 

 before an opinion is pronounced upon the nature of phenomena 

 the order of which has not been followed from their commence- 

 ment to their termination*. 



It now remains for me to direct attention to forms of Actino- 



* In my notes on the presence of animal life at great depths in the 

 ocean (published in November 1860), and also in a paper in the ' Annals 

 and Magazine of Natural History' for July 1861, I directed attention, for 

 the first time, to the occurrence of the Coccolitbs (minute discoidal struc- 

 tures previously detected by Huxley in the material of the soundings, but 

 regarded by him as inorganic) in spherical cells, to which I accordingly 

 applied the name of Coccospheres ; and I further pointed out that as 

 entire Foraminiferous shells, and more especially those of Textularia and 

 Rotolia, are frequently met with in the soundings wholly made up of seg- 

 ments resembling these Coccospheres in every particular, these bodies 

 would appear to be connected with the reproductive process. Although I 

 have not had the opportunity of tracing the actual sequence, I think it highly 

 probable that the Sarcoblasts, to which I have alluded in a former page, 

 first become Coccospheres, and are then developed into the perfect shell 

 by the ordinary process of gemmation. Here, then, is a case in which the 

 difficulties attending the study of the reproductive phenomena in the 

 Rhizopods are yet further enhanced. I may take the opportunity of 

 stating that I have recently met with Coccospheres in great abundance in 

 dredgings from the English Channel. The means of clearing up the point 

 are therefore at hand. 



