102 E. RAY LANKESTER, ON THE 
means of their ciliated inductors and interiors, establish a con- 
tinuous current, setting from their internal to their external 
apertures, which, of course, carries 
off daily a certain amount of the 
perivisceral fluid, since the trum- 
pet-like inductors of the ciliated 
canals float freely in this liquid. 
Placed along the dorsal aspect of 
the worm’s body, my friend Pro- 
fessor Busk has pointed out to 
me a series of openings or pores 
of considerable size, which form a 
second means of exit for the peri- 
visceral fluid. They are situated 
nearly in the median line, and 
number three or four in each seg- 
ment. All do not seem directly 
to perforate the integument and 
subcutaneous muscular layers; 
but they vary in this respect, 
as also in their relative posi- 
tion, which is not subject to any 
regularity. One of these orifices, 
situated in the median dorsal line 
of the segment, appears always to 
be larger than the others, and 
penetrates directly to the perivis- 
ceral cavity (fig. 9). That these 
Openings form a very ready and 
frequent means of escape to the 
“colourless fluid’? may be ascer- 
tained by handling a large earth- 
worm, when some considerable 
quantity of colourless fluid is 
nearly invariably found to escape 
from its dorsal surface.* 
* The following are Prof. Busk’s notes 
on the subject, which, with Fig. 1, he has 
kindly given me to make use of. 
LUMBRICUS TERRESTRIS. 
Large specimen, with clitellus, &c., 
apparently well developed. Killed with 
chloroform, and the cuticle stripped off. 
Surface presented pores as shown in 
figure No. 1. 
The range of median dorsal pores com- 
menced in the interspace between the 8th 
