MONO 
Inferior degree, ,the furprifing property of the genus 
aphis, viz. that of producing a feries of already-impreg¬ 
nated defendants. It is fliown, greatly magnified, at 
%■ 2> 
17. Monoculus longifpinus : tail infledled ; (hell ferru- 
late before, and prickly behind. Found in frefii water. 
The fliell is oval, white, and pellucid, ending behind in 
a ftrong fpine ferrate each fide, and half as long as the 
fliell; it has eight legs. 
18. Monoculus quadrangula: tail infledled ; fliell qua¬ 
drangular, unarmed. Found in ftagnant pools. The 
body is fometimes red; and it has fix legs. 
19. Monoculus fimus: tail infledled; fliell oval, un¬ 
armed. Found in marfhes. Tile fliell is pellucid, and 
yeliowifli. 
20. Monoculus redliroftris : tail infledled; hind-head 
with two projedting horns. Inhabits marflies. The fliell 
is oval, pellucid, with gaping valves, and ciiiate on the 
fore-margin; the tail confilts of two long briftles ; legs 
fix to eight. 
21. Monuculus curviroftris : tail infledled ; the front 
has two infledled horns. It is found in pools. The fliell 
is hairy on the fore-margins ; front has two pendent 
horns; the tail ends in two hooks ; it has eight legs. 
22. Monoculus mucronatus : tail infledled ; fliell ovate, 
beneath infledled, and prickly behind. It is found in 
marflies; fwims on its back on the furface of the water. 
The Ihell has four black dorfal ilreaks; it has twelve 
legs- 
23. Monoculus cryflallinus: tail infledled; oblong, 
cryftalline; head with two fliort horns at the tip. Found 
in frefli water. The body is white and pellucid, with 
twelve hairy legs. 
24. Monoculus pediculus t tail refledled. It inhabits 
frefh water. 
25. Monoculus fetifer: tail ftraight; {hells with long 
tufts of hair at the angles of the valves. Inhabits ftag- 
nant pools. The fliell is oblong, pellucid, and cryftalline ; 
the antennae have three branches ; the legs, which are 
eight, or more, are very hairy; and the tail is divided at 
the tip. 
III. Cythera; with a Jingle eye and a bivalve Jhell; antenna 
fimple. 
26. Monoculus viridis : fliell ovate, downy, green ; fore¬ 
legs falcate, and ferrate within. It is found in fea^water 
on fuci and confervse. 
27. Monoculus luteus: fliell ovate, gibbous, glabrous, 
pale yellow. Found on fuci. 
28. Monoculus flavidus : {hell oblong, glabrous, pale 
yellow, pellucid. It is found frequently on the Fluftra 
lineata. 
29. Monoculus gibbofus : fliell ovate, liifpid, and gib¬ 
bous each fide. Found on ulvae. 
30. Monoculus coardlatus : fliell ovate, glabrous, and 
contradled in the middle. It inhabits fuci. The ihell is 
of a greenifli hue, with a black eye. 
IV. Cypris ; a Jingle eye and bivalve Jhell; antenna tufted 
at the tip. 
31. Monoculus detedlus ; {hell oblong, white, pellu¬ 
cid ; tail with two briftles. Inhabits ditches. It has four 
legs ; the fore ones recurved, hind ones refledled. 
32. Monoculus ftrigatus : fliell kidney-fliaped, brown, 
with three white bands. Found in muddy ruts. The 
fliell is glabrous ; the antennae have eleven briftles. 
33. Monoculus ornatus : ihell ovate, finuate beneath, 
on the fore-part; and variegated with white, green, and 
fulvous. 
34. Monoculus pilofus: Ihell ovate, brown, ciiiate be¬ 
fore and behind. This fpecies is found in the nedlaries of 
the Utricularia minor. 
35. Monoculus candidus: fliell ovate, obtufe, fnow- 
white, immaculate. It is found in marlhes. 
CULUS. 687 
36. Monoculus Irevis: fliell ovate, obtufe, glabrous, 
greenifli. Inhabits ditches. 
37. Monoculus vidua : fliell ovate, white, with three 
black bands, two in the middle, and one on the fore- 
margin. Found in muddy water. 
38. Monoculus telemus: fliell fub-globular, three¬ 
toothed behind, with a truncate lip on the fore-part. It 
is found at Algira, and is pellucid. Some naturalifts 
imagine that it does not belong to this genus. 
39. Monoculus lenticularis : fliell comprefied and len- 
tiform. Found in Finland. 
40. Monoculus conchaceus : fliell ovate, dowmy. Found 
in ftagnant water. This is an Englilh infedl. The body 
is green, opaque, with yeliowifli legs ; abdomen nearly 
two-lobed, and fulvous, with a black circle in the mid¬ 
dle : it contrails itlelf within the (hell, and fwims on the 
belly. 
41. Monoculus fafciatus : fliell oblong, whitifli, with a 
green band behind the eye. Found in ftagnant water, 
and refembles a grain of barley. 
42. Monoculus monachus : fliell glabrous, yellowy 
edged with black ; opaque, truncate before, and rounded 
behind. 
43. Monoculus craflus : fliell oblong, gibbous, yeliow¬ 
ifli, with an oblique abbreviated fulvous band. It inha¬ 
bits fenny places. 
V. Amymone; with a Jingle eye and univalve Jhell; an¬ 
tenna two. 
44. Monoculus fatyrus: fliell ovate, pellucid, and emar¬ 
ginate behind ; antennae obtufe ; tail truncate, and cleft 
in the middle. 
45. Monoculus filenus : {hell ovate, opaque, and fub- 
marginate behind ; laft joint of the antennas fubulate. It 
is found in ditches filled with the leaves of trees. 
46. Monoculus masnus : Ihell oval; antennae horizon¬ 
tally extended ; body truncate at the bale. Inhabits lea- 
water ; and fwims on its back. 
47. Monoculus faunus : fliell ovate, pellucid, and 
emarginate behind ; laft joint of the antennas fubulate. 
Found in ditches among duck-weed. Antennas bent 
back.. 
48. Monoculus bacchus: {hell ovate, emarginate be¬ 
hind, and ending in two briftles. It inhabits rivers. 
Antennae ftretched forwards. 
49. Monoculus thyas: fliell dilated, linear; antennae 
incumbent. Found in {linking fea-water. 
50. Monoculus bradleatus : fliell globular, pellucid, 
unarmed ; legs fix, antennae obtufe. Found in frefli 
water. 
51. Monoculus faltatorius : fliell oval-oblong, pellucid, 
and briftly behind. 
VI. Argulus ; with univalve ficlls, and two eyes placed 
beneath. 
52. Monoculus charon : fliell pellucid, legs four. Found 
in ditches. The eyes are lpherical, remote, deep black, 
with four capillary circles round them. 
53. Monoculus delphinus: fliell gibbous; legs eight. 
Inhabits rivers. 
54. Monoculus armiger : legs fix. 
VII. Limulus ; with bivalve Jhells, and two eyes placed on 
the bach. 
55. Monoculus polyphemus, the gigantic monoculus : 
fliell orbicular; the future lunate, and toothed behind ; 
tail fubulate, and very long. This fpecies inhabits the 
Indian Ocean ; and is the largeft infedl known, the body 
fometimes meafuring two feet in length, and the tail two 
more. We may therefore very reafonably agree with 
thofe who urge that a claflification of crujiaceous animals is 
much wanted. Thefe enormous infects are faid to be ge¬ 
nerally found in pairs, or male and female fwimming to¬ 
gether. The colour of the whole animal is a yeliowifli 
brown; 
