ftECENT MEMOIRS ON FRESHWATER RHIZOPODA. 335 



granules, sometimes with only a few, and sometimes these 

 were absent. Hence, surely, according to the laws of 

 priority the name of the rhizopod should stand as Cochlio- 

 podium vestihitn (Archer), Hertwig et Lesser. Notwith- 

 standing, then, as I believe, the unity of the forms, I feel 

 satisfied, with Hertwig, that " Cochliopodium vestifu77i" not 

 only specifically distinct from every other rhizopod, but that 

 a special genus is necessary for it. 



And although a distinct genus is doubtless necessary, my 

 referring the form to Amphizonella was probably a more 

 pardonable error than the one more frequent, that of making 

 too many genera. But my great error was in the interpre- 

 tation of the halo often seen around the form ; this is not due, 

 as I at first thought, to the temporary pouring forth through 

 the outer envelope of a pellucid sarcode, but to the occa- 

 sional eversion through the frontal free opening of so much of 

 the sarcode-body (as first correctly pointed out by Hertwig 

 and Lesser), as forms a flattened base projecting beyond the 

 edge (formed by the double contoured envelope, which, 

 although flexible, is somewhat comparable to that of Arcella), 

 and on which projecting portion of the body-mass the rhi- 

 zopod stands or moves (by its contractility), the whole 

 somewhat comparable to the "foot" of a molhisc, and 

 by which it sometimes sticks to the slide in one and 

 the same place with a considerable tenacity, even upon force 

 applied to eff"ect its removal. 



Whilst this envelope (not to call it a test) is quite flexible, 

 following any change of figure of the body-mass, and assum- 

 ing an expanded shape at the vacant opening for emission of 

 pseudopoda, Hertwig and Lesser deny that the pseudopodia 

 have the power to become projected through it at any other 

 point. But their concluding paragraph on this form, and 

 the figure they there refer to,^ seem, taken together, to show 

 they must have really observed this phenomenon, which is 

 probably very rare. It cannot be doubted that the figure 

 referred to represents a Cochliopodium, and probably only a 

 small form of one and the same species, which occurs of 

 very varied sizes, some very minute, the latter presumably 

 young examples. There are there shown three places (for 

 the third must be behind to account for the pseudopodia 

 seen to the left), whence pseudopodial stems emanate. (See 

 our Plate XXI, fig. 8). 



These authors have not met with the green form described 

 by me. There cannot be a doubt, I venture to hold, but 

 that the chlorophyll-granules, when present, just as much 

 ' Loc. cit., Bd. X, Suppl., t, ii, f. viii, A. 



