253 Mr. H. J. Carter on Fecundation 



therefore requested to make this correction in all my previous 

 measurements where these divisions are mentioned, and to allow 

 for this generally, indeed, in all my measurements. 

 [The necessary alterations have been made in the present paper. — Ed.^ 



EXPLANATION OF PLATE VIIL 



N.B. All the figures in this Plate have been delineated as nearlv after 

 nature as the circumstances of the case would allow ; and in order that 

 their relative size may be seen, all, with the exception of figs. 6, 7 and 8, 

 have been drawTi on a scale of l-12th to l-5400th of an inch. 



Fiff. 1. Eudorina elerjans, in its first stage of development, 9-5400ths of 

 an inch long, comjiosed of sixteen cells, surrounded by a gelati- 

 nous envelope, through which their cilia project : a, four anterior 

 cells in which the eye-spot is visible ; b, gelatinous envelope. 



Fig. 2. Section of ditto, shov\'ing — a, gelatinous envelope ; b, original cell- 

 wall ; c, internal cell enclosing axial cavity ; d, interspace between 

 original and internal cell-walls, in vs'liich the green cells are situ- 

 ated ; e, nucleus ; /, eye-spot ; y, cilia ; h, canals through gela- 

 tinous envelope for the passage of the cilia. 



Fi(j. 3. Eudorina elegans in second stage of development, 30-5400ths of 

 an inch long ; composed of thirty-two green cells, each of which 

 is 3-5400tbs of an inch in diameter, exclusive of the capsule in 

 which it is enclosed : a, a, a, a, s])ermatie cells, now undistin- 

 guishable from b, b, b, the female cells ; c, shaded cell ; d, nucleus; 

 e, e5'e-spot ; /, contracting vesicle ; g, crenulated form of poste- 

 rior extremity ; h, nuclei in plurality. 



In this, as well as in many other of these figures, the principal 

 part of the cells and detail connected with them, as well as the 

 shading, has been omitted, to save trouble, one or two eomjilete 

 ones being sufficient to show what the rest would be if all were 

 properly filled in. 



Fig. 4. Ditto, ditto, ditto, with the contents of the four anterior or sper- 

 matic cells transformed into tufts of spermatozoids respectivelj^, 

 — the presence of the eye-spot and movements of the cilia of the 

 parent-cell indicating that she is still alive, though the cilia of 

 her progeny are already waving in her interior : c, c, shaded 

 female cells. 



Fig. 5. Ditto, with three of the spermatic cells burst, and their spermato- 

 zoids scattered throughout the interspace between the outer and 

 inner cell-walls, where they are vigorously applying themselves 

 to the capsules of the green cells : a, spermatozoids ajiparently 

 within the capsule ; b, unruptured s])ermatic cell. 



In this and in the foregoing figure, several of the green-cells 

 are omitted, to avoid confusion. 



Fig. 6. Single spermatic cell with tuft of spermatozoids more magnified, 

 showing — a, capsule ; b, mother-cell ; c, eye-si)ot. 



Fig. 7. Spermatozoids more magnified, to show the power they have of 

 elongating themselves. 



Fig. 8. A single cell of Eudorina in the second stage of development, but 

 under the Pandorina-fovm, that is, where the contents of all the 

 cells have imdergone the spermatic mode of duplicative subdivi- 

 sion, but stop at sixteen or thirty-two, and pass into small cells 

 of the ordinary form ai'vanged iu a tabular manner, like Goniurn ; 



