202 
BRITISH ENTOMOSTRACA. 
In the female, as I have already mentioned, the second 
and third are united ; and running across its centre, we 
may see a small canal which opens on each side where 
the external ovary is given off, and in all probability fur- 
nishes the envelope which contains the ova. This canal 
has a direct communication with the internal ovary. 
The tail consists of two long lobes, making it appear 
bifurcated, each lobe giving origin to four plumose setae, 
the two intermediate of which are much the longest, and 
have near the upper extremity a small joint, which adds 
much to the suppleness of these fine organs. 
The internal ovaries are tolerably large, and divaricate. 
The external ovaries, of the same colour as the adult, con- 
tain in old females thirty or forty eggs on each side. The 
length of this species is from ^th to T 9 5 th of an inch. 
The Cyclops quadricornis differs very much according 
to age, locality, &c.* Jurine enumerates seven distinct 
varieties in the neighbourhood of Geneva. I have met 
with several in the vicinity of London, which I have been 
sometimes almost tempted to consider as distinct species. 
Yar. a , elongatus. — Ramdohr’s figure corresponds 
exactly to this variety. It is of a dull gray colour, and is 
of an elongate and narrow form. The thorax, abdomen, 
and caudal segments, as well as the long filaments attached 
to the tail, all partake of the same general elongate figure. 
The antennae, however, are a little shorter than in the 
other varieties. The segments of the thorax and abdomen 
are more distinct (t. XXIV, f. 3.) 
Cyclops quadricornis, Bamdohr, Beitrage, t. 1, f. 1. 
— Kocht Deutsch. Crust., h. xxi, t. 11. 
Cyclops agilis, Kochi 1. c., h. xxi, t. 3. -V- wb 
Var. b .— Jurine’ s figures of the vars. rubens , albidus , 
and viridis agree with this variety. It may be considered 
the type of the species. The thorax is more or less com- 
* “ Yariat colore albida, fulvesccntc, viridi et rubro.” — Miill., 1. c., p. 112. 
