166 SIDNEY F. HARMER. 
Fics. 7 and 8.-From an experiment in which very little indigo-carmine 
had been taken up by leucocytes. 283rd hour. Back views. Polypide buds 
aud other structures not represented. Notice the indigo-carmine contained 
in the two green masses in the ‘ brown body.” 
Fig. 7. The zocecium has a somewhat abnormal shape. The ‘lateral 
cords” contain a quantity of indigo-carmine, and are less uniform in 
calibre than in zocecia with functional polypides. 
Fig. 8. The lateral cords have broken up into several portions. 
Fie. 9.—From an experiment in which the leucocytes, &c., had absorbed 
an unusually large quantity of indigo-carmine. 476th hour. Back view. A 
new polypide bud is developed. The ‘brown body” appears to be absorbing 
indigo-carmine from the leucocytes, which have, however, deposited the 
greater part of their pigment in continuous deep blue strands situated in the 
body-cavity. 
PLATE III. 
Fics. 10—12.—F. papyrea. Successive stages in the formation of the 
(ectodermic part of the) polypide bud (Zeiss, DD). 
Fic, 13.—F. papyrea. Normal excretory (?) cell from endocyst, with 
natural pigment (Zeiss, +; oil immersion). 
Fig. 14.—F. papyrea. Normal funicular tissue, with colourless refrac- 
tive granules, giving a starch-like reaction with iodine (Zeiss, F). 
Fig. 15.—F. papyrea. Bismarck-brown. 215th hour. Portion of one of 
the lateral cords (Zeiss, F). 
Fic. 16.—Bugula avicularia. Indigo-carmine. 72nd hour. Side view. 
Rough sketch of the alimentary canal, to show the distribution of the granules 
which take up indigo-carmine. Parts of the stomach, &c., are green, as the 
natural blue of the indigo-carmine contained in the granules is masked by the 
normal pigment of these structures. In the rectum, in which the granules 
are practically colourless, the blue colour is not obscured (Zeiss, DD). 
Fic. 17.—B. neritina. Indigo-carmine. 316th hour. Back view. The 
polypide, which has been completely developed since the beginning of the 
experiment, is not quite mature. The arrangement of the leucocytes in the 
meshes of the funicular tissue is well seen (Zeiss, C). 
Fic. 18.—B. neritina. Bismarck-brown. 143rd hour. Portion of the 
funicular tissue of a colony in which a very large quantity of the pigment 
had been absorbed. At 4 is seen a cell whose granules have an almost 
normal appearance. The greater part of the pigment taken up by the 
funicular tissue has been deposited in the form of dense brown masses, leaving 
the rest of the tissue hyaline. Most of the vacuoles of the leucocytes con- 
tain Bismarck-brown in solution, but one or two of them still remain colour- 
less (Zeiss, F). 
