44 
BRITISH ENTOMOSTRACA. 
(t. IV, f. d), can nearly cover the others, toothed, and, as it 
were, vandyked round its external edge, and folding up 
like a fan when the animal does not use it. These organs 
are generally carried by the animal rolled round under 
the head, and, as Shaw says, somewhat in the same 
manner as a butterfly carries its proboscis, their situation 
being externally visible only by a protuberance. During 
copulation, however, they become extended in a straight 
line, and when so, they nearly equal in length the main 
part of this curiously -formed organ.* These prehensile 
inferior antennae are used by the animal to seize hold of 
and retain the female in copulation, and seem exceedingly 
well adapted for the purpose. In the female (t. IV, f. e) 
they are differently and much more simply constructed, 
being merely in the form of two short, stout, and some- 
what sharp-pointed and flexible horn-like bodies, pro- 
jecting forwards when the animal is in the water, with 
a slight curve downwards, and not provided with any of 
the appendages described above as belonging to the male. 
The superior antennae, however, are precisely similar to 
those of the male. 
The eyes (t. IV, f. Fa) are very large, black, convex, oval- 
shaped, and composed of an immense number of small 
lenses, covered with a transparent cuticle. They are 
situated at the sides of the head, and are fixed upon 
considerable-sized peduncles, which take their origin 
from nearly the same part of the head as the antennse, 
and which are conical-shaped and moveable, the ani- 
mal having them almost always in quick motion in 
all directions.! In the centre, between these organs 
* Prevost finds much fault with Shaw’s figure of this curious antenna, 
especially with this proboscis-shaped portion of it. When fully extended, 
however, as when compressed between two pieces of glass, the figure given 
by Shaw, though ill proportioned and roughly executed, is a very fair repre- 
sentation of it. Jurine’s figures, though more elegantly executed, exhibit 
it such as I have seen it in a very young male only partially extended. 
Shaw, however, does not figure nor describe the membrane connected with 
the four appendages, and erroneously represents only three of these in his 
figure. 
f Burmeister has described the structure of the eye of the Branchipus 
