126 Mr. H. J. Carter on the Cell-contents of the Characece. 



the mucus-layer of the root also is preceded by the presence of 

 hyaline vesicles, as well as that of the cell of the stem ; shows also 

 first position of the cytoblast, viz. at the free end of the root-bud. 



Plate IX. 



Fig. 1. Dark green spherical cyst appearing in the internodes of Nitella at 

 the commencement of decomposition (see p. 14, loc. cit.), of 

 different sizes, but the largest about 100th of an inch in diameter; 

 the green colour arising from distension with the green disks and 

 other contents of the internode. 



Fig. 2. Ditto after the formation of a secondary cyst circumscribing these 

 contents. 



Fig. 3. Ditto, with the contents of the secondary cyst divided into four 

 ciliated sacs : (a) effete matter or green disks thrown off; 

 {b, b) monads between the two cysts. 



Fig. 4. Ditto, with the contents of the secondary cyst divided into two sacs 

 only, which are ciliated, and contain respectively a portion of the 

 green disks in their interior. 



Fig. 5. Ciliated sac fully developed, now assuming the form of Otostoma. 



Fig. 6. Otostoma (H. J. C.) about 100th of an inch long: (a) lateral view 

 of plicated buccal cavity ; {b) spherical vesicles of different sizes, 

 which together with mucus fill up the abdominal cavity ; {b) one 

 of these vesicles magnified, containing five smaller ones situated 

 on one side and filled with a brown yellow fluid. 



Fig. 7. Ditto : {a) oral orifice, ear-shaped ; (c) fusiform organ ; (c?, d) con- 

 tracting vesicles ; (e) pellets of green food, which, when present, 

 with the mucus and spherical vesicles mentioned in fig. 6, fill the 

 abdominal cavity; (/) anal orifice. 



Fig. 8. Ditto, showing arrangement of cilia over the surface. 



Fig. 9. Portion of a filament of Spirogyra just after conjugation, showing 

 (a) a cell containing a development of spherical cells filled with 

 yellowish refractive granules ; (6) a cell containing a development 

 of tubulating cells also filled with yellowish refractive germs or 

 granules ; {b') exit of the latter ; (c) a spore destroyed by the 

 same development ; (d) a cell in which a fitter of monads has 

 been developed, having in addition to polymorphism a single 

 cihum attached to them respectively, and hence frequently 

 assuming the form of young Astasice ; (d') the same monads 

 after having left the cell. Monads about l-2150th of an inch in 

 diameter. 



Fig. 10. Two cells of a filament of Spirogyra, showing (b) a spore de- 

 stroyed by the tubulating cell ; (c) one of the tubes leading 

 through the septum of the cell to insert itself into the sound 

 spore of the next cell. 



Fig. 11. Euglena {Crumenula, Dujar. (?)) filled with embryonic cells (?), 

 also showing the nucleus and its cell, and the " red spot " or body 

 attached to its proper cell : (a) vertical view of embryonic cell j 

 {b) lateral view of ditto. 



Fig. 12. Ditto, with embryonic cells and general contents much deranged ; 

 also presenting faint traces of segmentation of another deve- 

 lopment. 



Fig. 13. Ditto, with a few only of the embryonic cells left ; the green 

 colouring matter gone, and the whole contents of the Euglena 

 yielding to the development of eight or ten spherical cells filled 

 with minute granules of equal size ; (a, b) the same spherical cells 



