476 
KDITH M. MUSOUAVE. 
EXPLANATION OF PLATES 26 and 27, 
Illustrating Edith M. Musgrave’s paper on “ Experimental 
Observations on the Organs of Circulation and the 
Power of Locomotion in Pennatulids.” 
Abreviations. 
Ap. Apertm-e. Ax. Axis. Ax. 8 . Axial sheath. B.D.Ap. Basal 
dorsal aperture. B.V.Ap. Basal ventral aperture. B.W. Body- wall. 
C. and Ca. Canals. D. Dennis. D.Ap. Apertui’e leading from dorsal 
canal to exterior. D.C. Dorsal canal. D.M.S. Delicate musciilar 
sheath encircling the stalk near the base. D.P. Dorsal pores. Ep. 
Epidermis. Ex.C. Exhalent current. D.S.T. Vacuolated tissue with 
deeply staining cells. F.Ap. False aperture often seen in preseiwed 
specimens. G.Ax. Growing tip of axis. Iii.C. Inhalent cun-ent. 
L. Polyp bearing leaf. L.Ap. Lateral aperture near the base of the 
stalk. L.C. Lateral canal. L.M. Longitudinal muscles. L.M.P. 
Laminate muscular processes. M. Brownish earth-like matter on dorso- 
ventral septum. M.A.A. Muscular apparatus controlling movements 
of axis. M.B. Muscle-bands. Mg. Mesogloea. M.S.Ax. Muscular 
sheath encircling the axis near the apex of the I'achis. Muc.C. Mucus 
cells. N.D.S. Naked dorsal streak. Oh.M. Oblique musculature 
supported by dorso-ventral sejAum. if. Rachis. S.C.C. Small canals 
connecting dorsal and ventral canals. Si. Siphonozooids. Sp>- Spicule. 
Sph.M. Sphincter muscle regulating dilatation and contraction of 
stalk. Sp.T. Spongy tissue. St. Stalk. T.Ax. Termination of axis. 
Th.B.W. Ring-like thickening of the body-wall in the region of the 
insertion of the oblique muscles. T.Z. Thickened zone. T.Zo. Terminal 
zooid. V.Ap. Aperture from ventral canal to exterior. V.C. Ventral 
canal. V.L. Young leaves. F.S. Vertical septxmi. Y.St. Young siphono- 
zooids. 
PLATE 26. 
Figs. 1-9 
Fig. 1. — Pennatula luibra; x 8. Basal portion of the stalk with 
cut edge as transverse section. While living the specimen had been 
injected in the middle of the dorsal region of the rachis with finely 
powdered particles of carmine in suspension in sea-water and later 
by a second injection of methylene blue in solution in sea-water. 
The deposition of carmine particles on the walls and in the lumen of 
the canals is shown. The distribution of the methylene blue solution in 
