CONJUGATION IN THE CRAYFISH, CAMBARUS AFFINIS 261 
coming locked with the second both together were raised as far 
as possible to be at right angles to the body. The right and the 
left stylets acted together, yet one often moved a little ahead of 
the other for a short distance only. 
These preliminary experiments show merely that conjugation 
between species may take place to some extent. Whether 
sperm transfer may be thus accomplished remains for future ex- 
periment to show. 
This is of import here merely as showing the general nature of 
the instinct of the male and the similarity in the structure and 
use of the organs of sperm transfer in the different species of 
Cambarus. 
CONCLUSIONS 
The most complicated activities of crustaces are those proc- 
esses of conjugation that bring the sperm where it may ultimately 
meet the eggs. 
In the crayfish, Cambarus, the sperm though injured by water 
is transferred from male to female while under water. The pro- 
tection of the sperm involves many habits and organs of male and 
of female. In the female a peculiar receptacle stores the sperm 
till special habits and secretions bring it safely in contact with the 
eggs outside of the body. In the male three pairs of organs are 
devoted to the protection of the sperm while being transferred to 
the female. 
The processes of conjugation in this crayfish involve the accurate 
adjustment of the entire body of the male to the body of the 
female when placed as a mirror image of the male. 
The female plays a very inactive part while the male contracts 
most of the muscles of the entire body and limbs. 
In Cambarus affinis the pair of hooks on the third legs are neces- 
sary for sperm transfer and hence for the continuation of the race. 
They become fastened so as to form a fulcrum about which the 
muscles of the claws and body act. In structure they are but eleva- 
tions of the body-wall like other spines, but in this species they 
have no homologue on other legs. 
