OSCULA AND ANATOMY OF LEUCOSOLENIA CLATHRUS. 495 
Fie. 10.—Nuclei from a series of sections through the sphincter of an 
expanded large osculum. Hermann’s fluid, safranin, gentian violet, orange 
G. Zeiss, compens. ocular 8, apochr. F. 
Fic, 11.—Surface view of a relaxed sphincter of the osculum of a large 
colony. One third alcohol, picro-carmine, glycerine preparation. x 500. 
Fic. 12.—Surface view of another similar preparation. x 500. 12a, an 
isolated cell from this preparation. The upper (north) limit of Fig. 12 repre- 
sents the natural free edge of the sphincter. 
Fics. 13 a and 6.—Two views of another preparation similar to that from 
which Figs, 1] and 12 are drawn: 13 a, drawn with the microscope at the 
lower focus; 13 4, with the upper focus. x 430. 
Fic. 14.—Section from a series through the piece of sponge represented in 
Fig. 5. x 70. Abs. subl., borax carmine, hematoxylin. 
Fies. 15 a, 4, c.—Sections from a series through a contracted sponge. 
15 dis a portion of 15 @ more highly magnified to show the many-layered 
endoderm. Abs. subl., borax carmine, hematoxylin. 15 a ande x 120. 
