THE DIGESTIVE ORGANS OF THE ALCYONARIA. 359 
ticles of extruded undigested food. fv. Food vacuoles. g.c. Golden cells. 
gr.c. Granular gland cells. iz. mes. sp. Intermesenterial space. int.c. Inter- 
stitial cell. zé.c.s. Internal canal system. /.c¢. Longitudinal canals, 
1. m.f. Lateral mesenterial filament. m. Mesentery. m. ap. Mouth aperture. 
mg. Mesoglea. mg. b.w. Mesogloea body wall. muc.c. Mucous gland cell. 
mem. Nematocyst. xu. Nucleus. xze. Nucleolus. ov. Ovum.  v. mes. 
Mesenteries coloured red by ingested fish food. s. Stomodzum. sc. 
Scleroblast. sz. Siphonozooid. sp. Spicule. sph. Hole left by spicule after 
decalcification. sta. Starch. s¢.c. Stellate cell = ameeboid cell. ent. 
Tentacle. és. s.c. Transverse superficial canal. ». m. Ventral mesentery. 
v. m. f. Ventral mesenterial filament. zo. Zoo-chlorelle. 
PLATE 20. 
Fie. 1.—Alcyonium digitatum. A fairly young colony which has not 
yet assumed the digitate form. The zooids have been fed on carmined fish 
food, which can be seen through their transparent body walls. The colony 
was fixed and preserved in a fairly expanded condition by the hot formalin 
method. x 43. 
Fic. 2.—Alcyonium digitatum. Diagrammatic representation of the 
capture and course of food within the zooid. 
a. Capturing food. 
6. Tentacles contract slightly and enclose food. 
ce. Swallowing food. 
(The next stage—the grasping and squeezing of food by the ventral 
mesenterial filaments—is shown in Fig. 3.) 
d, The ventral mesenterial filaments are coloured red by ingested par- 
ticles of carmined fish food. 
The dorsal] mesenterial filaments take no part in the digestive process. 
x 10 (cam. luc.). 
PLATE 21. 
Fic. 3.—Alcyonium digitatum. Anthocodia of azooid which has been 
fed on carmined fish food. The excrescences on the pinnules of the tentacles 
are batteries of nematocysts. Grooves are shown between the bullate bases 
of the tentacles. The ventral filaments are shown embracing the food as it 
emerges from the stomodeum. x 10 (cam. luc.). 
Fie. 4.—Alcyonium digitatum. A mesenterial filament of a zooid 
which has been fed for two days on carmined fish food. The red patches are 
ingested particles of coloured food. x 67 (cam. luc.). 
. Fie. 5.—Sarcophytum glaucum. Transverse section through stomo- 
deal ectoderm to show granular and mucous cells. x 620 (cam. luc.). 
Fic. 6.—Sclerophytum densum. ‘Transverse section through stomo- 
voL. 49, PART 2.—NEW SERIES. 25 
