1026 The American Naturalist. [November, 
liquid, picric acid, chromic acid and Merkel’s liquid but the worms 
separated in hardening ; it was found, however, that when thrown into 
hot corrosive sublimate or even into boiling water the animals remain 
in a very natural position. This is due to the fact they are enveloped, 
especially in the region of the girdle, by a secretion that is coagulated 
by heat while the worms themselves are so quickly killed that they do 
not contract enough to change shape or to tear themselves apart. It is 
thus possible to obtain preserved pairs such as indicated in figure 11 
that very accurately indicate the appearance of the conjugating worms 
when alive. 
Even the large Lumbricus may be well preserved in pairs by plung- 
ing into actively boiling water and then hardening in alcohol. 
From figure 11 it will be seen that a pair of conjugating brandlings lie 
in a somewhat S shaped figure with the heads in opposite directions and 
the ventral sides turned toward one another anteriorly though posteriorly 
each may have it ventral side in the normal position, downward. Each 
may twist so that its anterior part lies on the side, the right or left in 
both worms. Itis noticeable that at two regions the worms appear con- 
stricted as if threads had been drawn about them but in reality it is 
only the firm envelope of mucous which binds them together. These 
two regions are separated by a long expanded region on the side of 
which may be seen the swelling about the male opening. Each con- 
stricted region is made up by the light colored girdle on one worm and 
the small dark colored region near the head of the other, a region of 
three rings that we will find subsequently are nearly enclosed by the 
girdle. The most anterior part of each worm may be free and is then 
immediately followed by the short region so very firmly clasped by and 
attached to the girdle. This free tip of the body contains seven rings 
in each worm. The following part that fits into the girdle contain 
three or four rings. The expanded region between this and the follow- 
ing girdle contains fifteen or sixteen rings and the girdle itself six or 
seven. Posterior to the girdle the animals may be nearly or quite free 
from one another so that the extend of the closely united region when 
the seven anterior rings are free, may be only twenty-four to twenty- 
seven rings of the entire one hundred, approximately, that make up the 
worm. The applied areas do not fit together exactly ring to ring and 
though they begin and end at the same distance from the head in each 
worm a fixed point, such as the male openings in the fifteenth ring, is not 
exactly opposite the same ring in each case. Approximately the male 
opening on the fifteenth ring of one is opposite the twenty-first ring of 
the other worm whereas we would expect it to be diagrammetically 
