SIDA. 
107 
1 . Sida crystallina. Tab. XII, figs. 3, 4 ; Tab. XIII, 
fig. 1 a-h. 
Daphne crystallina, Muller, ZooL Dan. Prod., No. 2405, 1776. 
Daphnia crystallina, Muller , Entomost., 96, 1. 14, f. 1-4. 
— Latreille, Hist. Nat. Crust., iv, 230. 
— Bose, Mem. d’Hist. Nat. Crust., ii, 281. 
Sida crystallina, Straus, Mem.Mus. Hist. Nat., v. 
— M. Edwards, Hist. Nat. Crust., iii, 385. 
Monoculus crystallinus, Gmelin, Linn. Syst. Nat. edit. 13th, i, 
3000, No. 29. 
— Manuel, Enc. meth., vii, 724, t. 265, 
f. 15-18. 
— Fabricius , Ent. Syst., ii, 493. 
Monoculus elongatus, Be Geer, Mem. servir Hist. Ins., vii, 470, 
t. 29, f. 1-4, 1778. 
Carapace or shell elongate- ovate, very transparent, 
truncate at inferior extremity. Head (t. XII, f. 3 a) large, 
with a projecting plate at the posterior part (f. 3 a, q). 
Eye large and round (t. XII, f. 3 b, 3 a, c). Body within 
the carapace very narrow, nearly straight. 
Abdomen has at the bend a projecting knob, with two 
long setae proceeding from it, and terminates in two long, 
stout daws, each of which has three spines on its inner 
edge (t. XIII, f. Ji). Between the knob and the termina- 
ting claws the inferior edge is beset with two rows of about 
twenty short spines. 
The superior antennae (t. XIII, f. a) are rather large and 
long, and armed at extremity with four short spines. They 
spring from a knob or eminence projecting a little out 
from the edge of the shell. The inferior antennae or rami 
are large (f. b). The basal joint is very stout and rounded, 
more than a third the length of the whole organ, and 
furnished with three short spines on anterior extremity. 
The two branches are rather short, compared with the 
size of the basal joint and the size of the animal. The 
external branch is divided into three articulations. The 
first, or lowest, is very short, and has a small spine at 
the outer angle ; the two others are nearly of equal length. 
