272 EDWARD A. MINCHIN. 
PLATE XI. 
Fics. 11a and 4.—Two consecutive sections taken across an osculum trans- 
versely but slightly obliquely. Osmic 1 per cent., hematoxylin. Zeiss, 
oc. 8, obj. F, apochrom. 272. 
Fics. 12a and 4 (Plate X).—Two sections of nodes of the sieve membrane, 
showing nuclei. 258, 
Fie. 13 (Plate X).—Section of sieve membrane, passing throughi ts origin 
from the wall of the osculum and four nodes. Zeiss, oc. 8, obj. F, apochrom, 
487 
a57 
Fics. 14a, 6, and c.—Three spicules. 222, 
Figs. 15¢ and 4.—Two spicules macerated out in glycerine, showing nuclei. 
Osmic half per cent, picro-carmine, glycerine. 
Fic. 16.—Two drawings of an isolated living collar-cell. Zeiss, oc. 8, 
obj. F, apochrom. 
Fic. 17.—A collar-cell from a preparation made with half per cent. osmic, 
and macerated out in glycerine. 
Fic. 18.—Collar-cells from a preparation fixed with half per cent. osmic, 
stained in picro-carmine, and macerated out with weak glycerine. Two of 
them are dividing. Zeiss, oc. 8, obj. F, apochrom. 
Fic. 19.—Collar-cells macerated out from the same preparation as Figs. 
5—8. Zeiss, oc. 8, obj. F, apochrom. 285. 
Fie. 20.—An ectoderm-cell. Osmic half per cent, glycerine. 
Fic. 21.—A pore macerated out, from the same preparation as Figs. 9a, 4, c. 
Fie. 22.—Section of the wall of the sponge. Flemming’s fluid, hema- 
toxylin, safranin. Zeiss, oc. 4, obj. D. 
