EXPLANATION OF PLATE T^.—ContinueA. 



Fig. 9. — Isolated chlorophyll-corpuscles q{ Spongilla flmiatilis. a. Seea 

 sideways to show the concavo-convex form of the chlorophyll-cap. b. Seen 

 from the concave surface, c. Two chlorophyll-caps developed upon one cor- 

 puscle of colourless protoplasmic substance, e. and/. Chloryphyll-caps with 

 adherent protoplasm. Diameter of the chlorophyll-caps averages ttooo*^ 

 inch. 



Fig. 10. — a. Corpuscle of dense colourless protoplasm, upon which six 

 chlorophyll-caps have developed, of which five are visible, b. Colourless 

 protoplasmic corpuscle and cap coloured green by chlorophyll. 



Fig. 11. — Colourless corpuscles isolated from amoeboid cells of a colour- 

 less SpongiUa. They are more angular in form, and denser in substance, 

 than the corpuscles upon which chlorophyll-caps are developed in green 

 specimens. 



Fig. 12. — Abnormal chlorophyll -corpuscle of SpongiUa, of very large 

 size (-aoVotl^ inch in diameter). Chlorophyll has developed all over the 

 surface of the corpuscle as a spherical envelope, whilst within are granules 

 coloured also by chlorophyll. It is seen in optical section, and closely re- 

 sembles the chlorophyll-corpuscles of Uydra viridis. 



Fig. 13. — Amoeboid cell of SpongiUa fluviatilis fixed withosmic acid, and 

 stained by picrocarmine. 



Fig. 14. — Amseboid cell from colourless specimen of SpongiUa, examined 

 in October. It has been fixed with osmic acid, and stained with picro- 

 carmine. Not only the nucleus {n) is stained, but the large amyloid 

 vacuole (similar to that of figs. 1, 3, and 4) has taken a very intense 

 carmine stain. The angular corpuscles {g) do not stain with carmine. 



Hydra. 



Fig. 15. — Endoderm-cell of Eydra viridis isolated by teazing, fixed with 

 osmic acid, and lightly stained with picrocarmine. It shows («) nucleus, 

 (c) chlorophyll-corpuscles, {g) irregular colourless bodies which stain faintly 

 with carmine, (tc) an ingested thread-ceU, {cc) minute rod-like chlorophyll- 

 corpuscles. 



Fig. 16. — Endoderm-cell of Hydra fuseahohiedi by teazing, fixed with 

 osmic acid, and lightly stained with picrocarmine. It shows (;?) nucleus, (6) 

 " foot " of the cell, {g) irregular corpuscles, colourless, bnt with da*k. 

 granules embedded in them. These appear to represent the chlorophyll- 

 corpuscles of H. viridis, as do the corpuscles {g) in fig. 6, of colourless 

 SpongiUa represent the chlorophyll-corpuscles of green SpongiUa. 



Fig. 17. — Isolated chlorophyll-corpuscles of Hydra viridis. a. The 

 spherical envelope of green-coloured substance is divided into three seg- 

 ments (surface view), b. Optical section of the same corpuscle, showing 

 green-coloured granules lying in the colourless protoplasm, enclosed by the 

 green envelope, c. Optical section of another corpuscle, d. An unusual 

 form of corpuscle, devoid of superficial green-coloured envelope, but with 

 numerous green -coloured granules embedded in the protoplasmic corpuscle. 

 e. Optical section of another normal chlorophyU-corpuscle. Fresh, without 

 reagents. 



Fig. 18. — ^Portions of endoderm-ceU of an olive -green coloured Hydra, 

 found in association with Hydra fusea. These portions separated when 

 the attempt was made to isolate endoderm-cells by teazing. Each contains 

 irregular, angular, scattered and aggregated granules, coloured blue-green 

 by chlorophyll. Fresh, without reagents. 



Fig. 19. — Brown-coloured corpuscles, very frequently observed inendo. 



