JUL 
system. The fishes of this order hare their 
ventral fins situated before the pectoral 
fins, and, as it were, under the throat. They 
are mostly inhabitants of the sea. Their 
body is sometimes covered with scales, 
and sometimes not. With a very few ex- 
ceptions, they have spines in the dorsal and 
anal fins, and their gills have bony rays. Of 
this order there are the following genera : 
Bleunins Kurtus 
Callyonimus Trachinns 
Gadus Uranoscopns. 
JULIAN period, in chronology, a system 
or period of 7980 years, found by multi- 
plying the three, cycles of the sun, moon, 
and indiction into one another. .See Chro- 
nology. 
This period was called the Julian, not be- 
cause invented by Julius Caesar ; since the 
Julian epocha was not received till the 
year 4669, but because the system consists 
of Julian years. Tliis epocha is not his- 
torical but artificial, being invented only 
for the use of true epochas; for Scaliger 
considering that the calculation was very 
intricate in using the years of the creation, 
the years before Christ, or any other 
epocha whatever, in regard that another 
person could not understand wliat year this 
or that writer meant; to remove such 
doubts in tlie computation of time, he 
thought of this period : which commencing 
710 years before the beginning of the world, 
the various opinions concerning other 
epochas may commodiously be referred to 
it. See Epocha. 
Tlie most remarkable uses of the Julian 
period are as follow: 1. That we can ex- 
plain our mind to one another, for every 
year in this period has its peculiar cycles, 
which no other year in the whole period 
has ; whereas, on the contrary, if we reckon 
by the years of the wmrld, we must first en- 
quire how many years any other reckons 
from the creation to the year of Christ, 
which multiple-inquisition is troublesome 
and full of difficulties, according to the 
method of other periods. 2. That the three 
cycles of the sun, moon, and indiction, are 
easily found in this, period. 3. That if it 
be known how the chronological characters 
are to be found in this period, and how the 
years of any other epocha are to be con- 
nected with the years of it, the same cha- 
racters also may, with little labour, be ap- 
plied to the years of all other epochas. 
JULUS, in natural history, a genus of in- 
sects of the order Aptera. Lip crenate, 
JU N 
emarginate ; antennm moniliform ; two 
feelers, filiform ; body long, semi-cylindri- 
cal, consisting of numerous transverse seg- 
ments ; legs numerous, twice as many on 
each side as there are segments of the body. 
There are fourteen species, of which we 
shall notice the J. indus, or great Indian 
julus, which is six or seven inches long; 
found in the warmer parts of Asia and 
America, inhabiting woods and other retir- 
ed places. It has 115 legs on each side, 
the body is ferruginous; legs yellow; the . 
last segment of the body is pointed. The 
most common species is the J. sabulostis, 
about an inch and a quarter long ; tlie co- 
lour brownish black, except the legs, which 
are pale or whitish ; it is an oviparous ani- 
mal ; and the young when first hatched are 
small and white, and furnished with only 
three pair of legs, situated near the head, 
the remaining pairs, in all 120, do not make 
their appearance till some time after. This 
species inhabits Europe, and is found in 
damp places and in nuts. The juli tribe 
are nearly allied to the scolopendr®, or 
centipedes, but their body instead of being 
flattened, as in those insects, is nearly cy- 
lindrical, and every joint or segment is fur- 
nished with two pair of feet, the number on 
each side doubling that of the segments, 
but in the scolopendrm the number of joints 
and of feet is equal on each side. The eyes 
of the juli are composed of hexagonal con- 
vexities, as in most of the insect tribe, and 
the mouth is furnished with a pair of den- 
ticulated jaws. AVhen disturbed the juli roll 
themselves up into a flat spiral : their gene- 
ral motion is rather slow and undnlatory. 
JUNCUS, in botany, rush, a genus of the 
Hexandria Monogynia class and order. Na- 
tural order of TripetaloideiE. Junci, Jus- 
sieu. Essential character: calyx six-leaved ; 
corolla none; capsule one-celled. There 
are twenty-nine species. The rushes have 
a simple grassy stem, without leaves or 
knots, or else knotty, with a sheathing leaf 
at each knot ; flowers terminating or late- 
ral, corymbed or panicled, with the branch- 
lets spathaceous at the base. 
These plants agree with the grasses in 
the glumes of their flowers, and the sheaths 
of their leaves ; they difl'er in having the 
stems filled with pith, whereas in grasses it 
is hollow. The rushes form an intermediate 
link between the grasses and some of the 
liliaceous plants, as anthericum, &c. 
They form naturally two divisions, one 
without leaves allied to scirpns, &:c. aird 
the other with leafy stems. But all chissical 
