282 Mr. H.J. Carter on the Fresh- and Salt-water 



ception of the trifling discrepancies in the general outline of the 

 fragment, is correct. To have cut the latter down to an exact 

 segment of a four-inch radius would have destroyed the uni- 

 formity of the plate, while the reader can easily do this for him- 

 self, if necessary. 



My object in giving such an enlarged view of a portion of 

 A. Eichhornii has not been so much to compare its size or 

 structure with that of the other Actinophryans as to bring 

 into view certain spherical bodies which are situated and ap- 

 parently developed in the intervacuolar sarcode, since it seems 

 to me that these are as much "reproductive cells" of Actino- 

 phrys as those which I have figured and called attention to, 

 from time to time, since 1856 up to the present day, in Spon- 

 gillce, Amoeba, Euglyphce, Difflugice, and, among the Foramini- 

 fera, in the living species Operculina arabica, and in fossil Num- 

 mulites, Orbit aides, &c. 



So little attention appears to have been paid to these bodies 

 in Actinophrys Eichhornii, that, although Kolliker is frequently 

 and justly quoted as an authority on the structure of this spe- 

 cies, in the last edition of Pritchard's ' Infusoria ' no allusion is 

 made to them beyond that at page 252, where this eminent 

 physiologist is stated to have enumerated among the general 

 contents of the body of Actinophrys " some separable nuclear 

 cells '" but whether these be the ones in question or not, the 

 context does not enable me to decide. Latterly, however, Dr. 

 Wallich has undoubtedly described and figured them in his ex- 

 cellent representations of A. Eichhornii (Annals, vol. xi. p. 450, 

 pi. 10. figs. 1 & 2 n n, 1863), and observes respecting them — 

 " These multiple nuclei are distributed here and there through 

 the protoplasm, each occupying a spherical cavity, which is 

 completely filled up by the granular matter, and quite distinct 

 in outward appearance from the polygonal soap-bubble-like 

 mass of which the rest of the body is constituted/' Any one 

 at all conversant with the subject will, with this description, 

 immediately recognize these bodies in my illustration; but whe- 

 ther they be derived from a subdivision of the nucleus, as Dr. 

 Wallich seems to conjecture, or not, is a question to which I 

 shall have to return presently. 



With the large specimens were others of all sizes, down 

 to ^-oth part of an inch in diameter (fig. 7), and, I dare say, 

 still smaller, if I had had more time to look for them ; but all 

 below a certain diameter failed to present the " reproductive 

 cells" mentioned. 



For a structural description I shall take one of the largest 

 specimens, and, to avoid all tedious repetition of what has pro- 

 bably been better stated before, confine myself briefly to a sum- 



