M O N 
the ova of Alh ; on being examined in the light with a 
magnifying glafs, they were difcovered to have an internal 
motion; fome that were fet at liberty in the water were 
feen to fwim with great rapidity like water-fleas. Riville 
feized one of thefe with a pair of forceps, which caufed it 
to (lied a luminous liquor of a blue colour, that illumi¬ 
nated the water to the diltance of two or three lines. 
Some of thefe animals were put into frefh water, which 
they furvived only a few feconds, and defcended, ftrug- 
gling, to the bottom of the veffel ; many. of them ren¬ 
dered much luminous fluid while dying. Riville defcribes 
this creature as being enclofed in a {hell refembling an al¬ 
mond, fplit along the fide, and notched at the upper end, 
which is fo tranlparent that all the internal parts are feen 
through it. The infect has four jointed antennae, fur- 
niflied at their extremities with long fetae. There are two 
feet armed with hooks; and below thefe, a thick foot ter¬ 
minating in feveral claws. The vifcera are contained in 
a round fac; and at the lower part of the {hell there is a 
number of azure-coloured globules, which Riville confi- 
dered as refervoirs of the luminous fluid, becaufe they 
became of a dull yellow colour when the animal was about 
to die; but they are more probably the ova, which are 
alfo vilible in this fituation in other teftaceous infeCts. 
The luminous liquor flied by the animal does not, Riville 
fays, mix with water, but floats on the furface like glo¬ 
bules of oil. By {training fome water from which the 
animals had been removed, limilar globules were left in a 
difiinCt form upon the cloth. From thefe circumftances, 
he was difpofed to believe that the globules he faw were 
really of an oily nature ; which opinion he was in a great 
mealure induced to adopt, from a preconceived theory, 
that all the luminous appearances of animals depend upon 
the occafional prelence of an oily fluid. Mem. Etrang. 
de l'Acad, des Scien. tom. iii. 
64. Monoculus brachyurus: fliell globular; tail de¬ 
flected ; antennas four. It is found in marflies. The 
lhell is pellucid, reddifli-brown when young, and green 
as it grows older, with a white eye 011 the fore-part, and 
a black one behind ; legs twenty to twenty-four. 
65. Monoculus fphasricus: lhell globular; tail infleCt - 
ed; antennae two. This fpecies is found among the 
duck-weed in ftagnant water. It is a native of Europe, 
and found frequently in this country. It is very minute ; 
the fliell is reddifli; it has twelve legs ; and the tail is fur- 
niflied with a fmall hook at the extremity, and concave 
beneath ; the ovariae are green. 
66. Monoculus quadrangularis: fliell quadrangular, 
hence its fpecific name ; tail infleCted ; antennae tw'o ; 
legs from twelve to fixteen, befides numerous fmaller 
ones ; the tail is armed with tw'o minute fpines at the tip. 
67. Monoculus lamellatus : fliell ventricofe ; tail in¬ 
flected, lamellate; antennae two. Found in ilagnant wa¬ 
ter. The lhell is convex ; eyes green ; legs capillary ; the 
tail has a broad ferrate lamina beneath, and two fpines at 
the tip. 
68. Monoculus trigonellus : lhell gibbous before; tail 
infleCted, ferrate; antennae four. Found in ditches. The 
ihell is ciliate, with a {harp probolcis ; antennae with three 
briAlesat the tip ; ovaries black. 
69. Monoculus truncatus : lhell ovate, and toothed 
behind ; tail infleCted, ferrate ; antennse four. Inhabits 
ftagnant waters. 
70. Monoculus longiroftris : fliell roundifli; prickly on 
the fore-part; tail infleCted. It inhabits rivulets. The 
probofcis is longer than the head, curved, and fubulate. 
71. Monoculus macrourus : lhell oblong ; tail Itraight; 
antennae four. It is found in lakes. The ihell is pellu¬ 
cid, whitilh ; legs eight; claw lanceolate. 
7a. Monoculus focors: fliell ovate; tail projecting, 
curved ; antennae two. Found in almoit all kinds of 
waters. The fliell is pellucid, without Arise, teeth, or 
fringe. It has four legs, and the tail is biculpidate at the 
tip. Tart on's Linn. Shaw's Gen. Zool. liarbni's Genera 
infeStnrum. Phil. TranJ". Donovan. 
you. XV. No. 1076. 
M O N GS§ 
MONOC'ULUS, or Monophthalmus, / [from poves, 
Angle, and oculus , Lat. or opfiatyio?, Gr. an eye.] A 
bandage in furgery, formerly much more employed than 
at prefent. It confiAed of a roller, ten or twelve feet in 
length, and about three inches in breadth. It was firlh 
fixed on the occiput, about a foot of the bandage being 
left hanging down. It was then carried obliquely round 
the head, over the forehead, to the occiput again. After 
being applied thrice round the head in this oblique di¬ 
rection, the remainder of the bandage was expended in 
more horizontal turns. The end, hanging down behind, 
was laAly brought over the vertex to the forehead, and 
the whole was fecured with pins. The chief ufe of the 
monoculus was to retain dreflings on the eye. The old 
furgeons had alfo a double monoculus ; but it fcarcely 
merits defcription,as itis now feldom or never made ufe of. 
MON'ODON, f. [Gr. {ingle-tooth.] The Narwal, or 
Sea Unicorn ; in zoology, a genus of the clafs mammalia, 
order cete, or cetaceous fillies ; of which the Linnaeart 
generic character is—-Two teeth in the upper-jaw, ex¬ 
tending ftraight forward, long, fpiral; fpiracle on the 
fore and upper part of the head. Dr. Shaw has altered 
the generic character, byuling the Angular, tooth project¬ 
ing, inflead of two teeth, becaufe, though he admits there 
are fometimes two teeth, yet, as the animal is generally 
found with one only, and becaufe the generic name mo- 
nodon is derived from that very circumltance, the altera¬ 
tion feems neceflary. Gmelin defcribes but one fpecies ; 
Dr. Shaw has added another (doubtful) from Fabricius. 
1. Monodon monoceros, the one-horned narwal: tooth 
(fometimes two) large and long. Our old writers de- 
lcribe the narwal as Axty feet long ; but that muA have 
been ere the whale-fifliery had begun to cut off" thefe enor¬ 
mous animals in their minority, and before they had at¬ 
tained their full growth ; and we are told that whales 
were formerly feen a hundred and twenty feet long. The 
narwal is of a more {lender make than the common 
Greenland whale; and its fat is in lefs abundance. It 
inhabits the feas of Iceland and Greenland, and is feen in 
the lame northerly regions with the reA of the cetaceous 
tribe. Nature has, however, diAinguiflied it from every 
otherinhabitantof the deep, by the formidable weapon, in 
the form of a tooth, which projects from its upper jaw. 
AmongA all that variety of armour which {he lias con¬ 
ferred upon her diflerent tribes in the animal kingdom, 
flie has contrived noinArument of deAruCtion fo dreadful 
as the horn of the narwal. This extraordinary inArument 
generally fprings from the upper jaw on the left fide? 
(when there is but one), into the focket of which it 
reaches a foot and a half. It is Ariated, and twilled in 
fpires, as we fometimes fee a bar of iron ; its length is 
from {even to eight feet, and of the thicknels of a man’s 
arm : it is of a white colour, harder and heavier than 
ivory. From the Aze of this weapon, moA naturaliAs 
conlider it as an horn, rather than a tooth ; but it refem- 
bles in every refpeCl the tulks of a boar, or an elephant; 
it rifes, like them, from a focket in the jaw ; it is of the 
fame Arong fubAance, and poflefles the lame lolidity. 
Willughby regards it as the only real example of an uni¬ 
corn afforded by nature ; and after a minute examination 
of all the fubflances that are impofed upon the public for 
the horns of the unicorn, he pronounces them impoli- 
tions on the credulity of mankind. This naturalifl had 
the greater merit in making a dilcovery of this nature, 
becaule in his time the capture of whales was not very- 
frequent, and the means of detection were proportion- 
ably few in number. The tooth of the narwal about 
a century ago was univerfally afcribed to fome land- 
animal : it has often been dug up among foflil fub- 
Aances, and from that circumltance it was naturally be¬ 
llowed upon a terreffrial owner. Pliny had long ago de- 
fcribed an animal refembling a horfe, with a Angle horn 
fpringing from the middle of its forehead : upon thi* 
animal, which a farther knowledge of nature has proved 
to be fictitious, the tooth of the narwal was unanimoufy 
si N conferred f 
