224 
BRITISH ENTOMOSTRACA. 
M. Siebold,* however, has had opportunities of studying 
them carefully, and the results of his observations, with 
his remarks on the method of copulation of Diaptomus, 
are so interesting and striking, that I will give them here 
at some length. The male having only the right antenna 
provided with the swelling and hinge-joint, seizes hold of 
the tail of the female with it, and grasping it tightly, 
curves himself up to her ventral surface. He then sur- 
rounds the base of her tail with the large hook of his fifth 
pair of feet. The female is at first restless, but she soon 
becomes more tranquil, and in this position they both fall 
to the bottom of the water, remaining fixed sometimes for 
hours together. The act of copulation itself, however, 
lasts only for a short time ; but what takes place during 
that short interval is very remarkable. “ A cylindrical 
tube, filled with a spermatic liquor, escapes from the sexual 
organ of the male, immediately after the connection takes 
place ; the male seizes this tube as soon as it has made its 
exit, and fastens it against the abdomen of the female, be- 
neath the vulva/ ’f The fifth pair of feet is most probably 
the organ by which the male seizes the tube ; but Siebold 
did not distinctly ascertain the fact. When it escapes 
from the male organ, it is by its rounded extremity ; and 
it would appear, that when the animal lays hold of it, he 
presses the neck of the tube with the tip of his foot against 
the first joint of the tail of the female, and as the neck of 
the tube contains a glutinous substance, it immediately 
adheres. 
Such is the operation, as described by Siebold from 
personal observation, and from which he concludes, that it 
is with the matter in these tubes that the female is fe- 
cundated. No female, he says, possesses a tube before 
copulation ; but immediately after the act is accomplished 
we see one fastened to her, near the vulva. If a male 
be examined, when in heat and before copulation take 
* Mem. de la Soc. des Scrutateurs de la Nature, de Dantzig, iii, part ii, 
1839 ; Ann. des Sc. Nat., 2d ser., xiv, 20-38, 1840. 
f Ann. des Sc. Nat., xiv, 28. 
