454 
EDITH M. MUSGEAVE. 
niiuate incision in the dorsal snrface of the middle of the 
rachis, an injection of finely powdered particles of carmine in 
suspension in sea-water was made, with the aid of a small 
syringe, into the dorsal canal. The injected fluid passed 
immediately to the base of the stalk, its presence being re- 
vealed by the transparency and tenuity of the body-wall in 
this region (fig. 1). Three quarters of an hour later no 
apparent change had taken place in any other portion of the 
colony, but at 8.15 o’clock the following morning a thin, 
viscid stream containing carmine particles was observed to 
ooze from a single pore at the base of the stalk. Similar 
streams, but more minute in quantity, were also observed to 
proceed from four small pores also hitherto unrevealed, in the 
median naked streak in the dorsal surface (fig. 5) about 
25 mm. from the extreme apex. 
About 10 a.m. the same day the ventral canal of the same 
specimen was injected from the ventral surface in a 
similar manner with a solution of methylene blue in sea- 
water, when a portion of the injected fluid was immediately 
discharged through the mouths of the more ventrall}^ situated 
siphonozooids and autozooids, while a considerable portion 
passed almost to the extreme base of the stalk and was dis- 
charged through an aperture which then only became 
apparent. Two basal apertures were thus revealed : one 
slightly dorsal to the other extruding particles of carmine, 
the second, slightly ventrally placed, discharging the solution 
of methylene blue. Several hours later, however, carmine and 
methylene blue were observed to emerge together from the 
ventral aperture. 
The two basal apertures thus revealed were afterwards 
found to be direct openings of the dorsal and ventral canals to 
the exterior (figs. 1 and 2). The experimental evidence of 
their presence and active physiological function in living 
specimens gives an affirmative answer to the controversy 
which has existed since the eighteenth century (pp. 443-445) 
as to whether Pennatulids have or have not a basal communi- 
cation with the exterior (figs. 1 and 2). 
