478 
EDITH M. IMTTSGRAVE, 
racliis of an injected specimen to show the extrusion of carmine particles 
from four dorsal pores (D.P.) ; X 2. Tliese are the apertures of small 
transverse canals, which in this portion of the rachis establish com- 
munications dorsally between the large dorsal canal and the exterior. 
The particular specimen differed from any other which I have examined 
in the presence of a group of unusually large siijhonozooids (Si.) in the 
region superior to that of the dorsal pores. Elsewhere the siphonozooids 
(Si.) are quite normal in character. 
Fig. 6. — Pennatiila phosphorea. Drawing of the dorsal surface 
of the uiiper portion of the rachis of a young colony, x 15, showing the 
terminal zooid and four dorsal pores (D.P.) from which, after injection, 
as in fig 1, carmine particles were extruded. 
Fig. 7. — Pennatula rubra. A portion of the dorsal surface of an 
injected specimen to show the extrusion of carmine particles from the 
mouths of the siphonozooids twenty-four hours after the injection was 
made. X 30. 
Fig. 8. — Pennatula rubra. Transverse section through the stalk 
near to the base ; X 15. On the left side two of the smaller apertures are 
shown (Ap.) which communicate by means of the spaces in the spongy 
tissue witli the ventral canal (V.C.). In the upper portion of the section 
a small canal (C.) is shown in the dorso-ventral septum (D.V.S.), which 
establishes communication between the lumen of the dorsal and 
ventral canals. Small canals (Ca.) are also shown leading from the 
large canals into the spaces of the spongy tissue (Sjj.T.). A very thorough 
and complete system of communication is established by means of similar 
canals throughout the colony, which is thus brought into communication 
with the external sea-water. The epithelial tissue lining the canals is 
much vacuolated (Fig. 0) and contains numerous deeply staining cells, 
which are prol>ably mucus-secreting, and are similar in character to cells 
composing the greater portion of the periphery of the base of the stalk. 
Immediately below this layer of vacuolated and deeply staining tissue, 
parallel with the periphery and outlining the large dorsal and ventral 
canals, is an extremely delicate sheath of transverse muscular fibi'es 
(T.M.F.), which becomes, however, much moi'e pronounced in the 
superior regions of the stalk. The spongy tissue occupies the whole 
of the space between the canals and the body-wall. 
Fig. 9. — Pennatula rubra. A portion of the vacuolated and 
deeply staining epithelial tissue which lines the dorsal and ventral 
canals as seen in a transverse section of the stalk ; X 800. A similar 
epithelial tissue covers externally the basal portion of the stalk. The 
endoderm in this portion of the canal is curioiisly papillate in form, 
and exti'emely vacuolated. It contains numerous deeply staining cells, 
which probably have for their function the secretion of mucus, and also 
send off into a supporting mesogloeal core numerous muscle-fibi’es 
