1022 The American Naturalist. [November, 
against and carefully examine one another. If the worm that is found 
is not mature or even if it is smaller than the seeker, greeting does not 
last long and the worm continues his search in some other direction till 
he succeeds in finding some other individual like himself 
He generally finds one waiting or else oe 
one o from its nile w thrusting his head into it. They undulate against 
one another; now one now the other drawing back is always followed 
by his companion. The movements soon become more active; they 
strike one another with their heads. 
At length they both lie still with the ventral surfaces near together. 
The body begins to undulate, especially at the girdle and within a few 
minutes the sucking action of the girdle comes into play to establish a 
more firm union of the two animals. The side parts of the girdle that 
bear the sucking disks are spread out in wing-like expansions while 
the ventral part is much drawn in. In this way a sort of tube is formed 
and in this the other individual is enclosed. 
The mutual adjustment of one to the other becomes more and more 
close and accurate while the undulations of the transverse muscles and 
of the girdle constantly increase. Meanwhile mucous flows copiously 
from the dorsal pores and from the girdle. Usually a Jot of young 
worms now assemble and greedily suck up the mucous 
The pair lie motionless for a good half hour before the seminal fluid 
could be seen flowing out 
Once I watched for a pair the day after wtopa; in vain, oe the 
following day I found one of the two in conjugation again. Conjuga- 
tion seems to be repeated so often that one may imagine a separate 
fertilization for each egg. 
n the above account all that refers to the actual transfer of sperm 
has been omitted as it contains many errors that have been corrected 
by our only reliable authority on this problem, Ewald Hering,’ who in 
1856 as a medical student in Leipzig made so careful a study of the re- 
productive organs of the earthworm that many years elapsed before his 
discoveries were rediscovered and introduced into text books in place 
of the erroneous views long lingering there. 
His account of the conjugation of earthworms is all the knowledge 
we have of the process, at present, and is here translated in full to 
make intelligible the facts that we have to add in regard to conjugation 
in the brandling. 
“ When conjugating the worms lie in opposite directions with their 
ventral sides applied to one another. By drawing in the ventral side 
1 Zeit. f. wiss. Zool., VIII, 1856. 
