360 EDITH M. PRATT. 
dzal ectoderm to show mucous gland cells.. The mucous secretion is seen to 
be oozing from many of the cells. x 608 (cam. luc.). 
Fic. 7.—Sclerophytum hirtum. Transverse section through the 
siphonoglyph, showing the extremely long flagella, which are about ‘03 mm: 
in length. x 608 (cam. luc.). 
Fic. 8—Lobophytum pauciflorum. Longitudinal section through 
the lower portion of the stomodzum of an autozooid, showing the termination 
of ectoderm and the continuation of endoderm into the ventral mesenterial 
filaments. x 312 (cam. luc.). 
Fie 9.—Alcyonium digitatum. Transverse section through an un- 
stained ventral mesenterial filament, showing amceboid ingestion of carmined 
fish food by the endoderm cells. Some of the ameeboid cells are shown with 
pseudopodia projecting into the ccelenteric cavity. Particles of undigested 
food (f. wz.) are being extruded from some of the cells. Gland-cells are not 
indicated, as they cannot be seen without the aid of staining reagents. 
xX 930 (cam. luc.). 
Fie. 10.—Alcyonium digitatum. Transverse section through a 
ventral mesenterial filament of a starved zooid, stained with iron brazilin. 
Granular gland cells (gr.c.) are extremely numerous. A few mucous cells 
are interspersed between the granular gland cells and the amcboid endoderm 
cells. There are no spaces between the gland cells at the periphery of the 
filament, but spaces are numerous in the middle of the filament. x 930 
(cam. lue.). 
Fic. 11.—Alcyonium digitatum. Slightly oblique section through a 
ventral mesentery of arecently fed zooid, similar to the one shown in Fig. 10, 
after staining with iron brazilin. This filament differs from that of a starved 
zooid (Fig. 11) in that the granular. gland cells are remarkably few in number 
and contain very few granules. The spaces occurring between the cells at the 
edge of the filament are probably empty gland cells which have discharged 
their secretion on to the food when it was embraced by the filaments. A few 
nematocysts, similar to those of the tentacles, are present. x 930 (cam. 
luc.). 
Fie. 12.—Sarcophytum ehrenbergi. Transverse section through a 
ventral mesentery to show the mesoglceal thickening near the free end, and 
the scarcity of gland cells in the feebly marked filament. x 416 (cam. 
lue.). 
Fic. 13.—Sclerophytum capitale. Slightly oblique transverse section 
through a ventral mesenterial filament in which zoochlorelle are extremely 
numerous and granular gland cells very few in number. This drawing illus- 
trates the reduction of the digestive surface in tropical forms, and the corre- 
sponding increased abundance of zoochlorelle. x 930 (cam. luc.), 
