a i 
unrolled state, they are readily examined by 
breaking almost any young shoot or leaf-stalk, 
and pulling the extremities gently asunder, when 
the uncoiled fibres appear to the naked eye like 
a fine cobweb. In stems furnished with pith, 
the spiral vessels usually occupy a circle imme- 
diately around it: thence they proceed to the 
veins of the leaves, and of all parts which are 
modifications of leaves. Duets are vessels in which 
the spiral fibre is incapable of unrolling. The 
turns of the coil sometimes touch each other, 
forming what are called closed ducts, which are 
only to be distinguished from spiral vessels by 
this character: often the turns are distant, or 
broken into separate rings placed at considerable 
intervals (annular ducts); sometimes they cross 
each other (reticulated ducts), or are broken up 
into short irregular bands. Occasionally nearly 
all these varieties may be observed in different 
portions of a continuous vessel. Ducts occur 
abundantly among the woody tissue of almost 
all plants. See the article Vascunar Tissur. 
Laticiferous tissue consists of a peculiar system 
of vessels, which have only recently been made 
known. The vessels of the latex are those in 
which peculiar products of plants (such as milky 
juice, &c.) are elaborated and contained. They 
are distinguished from all other vessels by their 
numerous anastomosing branches, and also by 
their irregular contractions and expansions. 
Their average diameter is said to be one-fourteen 
hundredth of an inch. Their old trunks are 
often very much larger; but their ramifications, 
which proceed to the surface of the organs, and 
form a most delicate net-work upon the hairs, 
are so minute that they are only to be disco- 
vered with the aid of the most powerful micro- 
scopes.— Gray. 
TIT, or Trrmousn,—scientifically Parus. A 
genus of passerinous birds, of the conirostrous 
family. They have slender, short, conical bills, 
with little hairs at the base, and with the nos- 
trils concealed among feathers; and they possess 
exceedingly active powers, and display remark- 
able agility, and flit constantly from branch to 
branch, and pass rapidly through a great variety 
of positions; and they are, in a considerable 
degree, omnivorous, and tear asunder the seeds 
on which they feed, and devour all insects whom 
they can find.and even kill and eat whatever 
small birds they happen to find sick or are other- 
wise able to master. Five or six species occur 
in Britain; and though differing in size, colour, 
and some other particulars, have a great simi- 
larity in habits, feeding, and general character. 
The tom-tit, or blue-headed tit, or blue whaup, 
Parus cceruleus, is, in many districts, the most 
common species, and in almost all a peculiarly 
interesting one, at once for its pretty appear- 
ance, for the erroneous notions which are gene- 
rally entertained respecting its habits, and for 
the war of extermination which is often carried 
on against it. See the article Hupar-Birps, The 
upper surface of its body has an olive-coloured 
plumage; the lower surface is yellowish; the top 
of the head isa fine blue; the forehead is white ; 
and the cheek is white, surrounded with black. 
He is so knowing a little fellow respecting the 
nicest morsels of his vegetable diet, and at the | 
same time so prying and impudent and fearless, 
that one can easily understand how he has ac- 
quired a very bad name among the great majo- 
rity of farmers and gardeners. “ He prefers what 
is delicate as well as nutritive, and is particu- 
larly fond of every sort of nuts and the larger 
seeds, which most resemble nuts in quality, such 
as the seeds of sunflower, hemp, pease, and the 
like. It may well be supposed that his smail 
beak, hard though it be, is inadequate to manage 
such large seeds in the way they are shelled by 
the linnet or the bullfinch; but the tom-tit is a 
most ingenious seed-breaker. In the case of a 
pod of Prussian-blue pease, for example, he will 
first peck a hole through the shuch or shaup to 
get at a pea; and this, when he has procured it, 
he fixes between his claws, while he hammers 
away at it with his little bill till he gets at the 
mealy kernel, which he hollows out and devours, 
leaving the empty shell. He does the same with 
a hemp seed, and it is surprising to observe how 
small a hole in the shell will sometimes suffice to 
enable him to get at the whole contents. Yet 
he certainly commits very few or trifling depre- 
dations on any sort of garden fruit ; and, upon 
the whole, may be considered as producing more 
benefit than injury to cultivators.” 
The long-tailed tit, Parus caudatus, is a com- 
mon and well-known species; and remains in 
Britain throughout the year; and frequents 
woods, shrubberies, and other places of retreat 
and shade. His total length is about 5% inches; 
the upper surface of his body has black plumage ; 
his wing-coverts are brown; the upper part of 
his head and all the parts beneath are white; 
and his tail is longer than his body. The female 
builds her nest on the branches of small trees, 
and roofs it over, and lays from 10 to 12 eggs. 
The cole-tit, Parus ater, and the marsh-tit, 
Parus palustris, have a considerable resemblance 
to each other, and are distinguished from the 
tom-tit by the black colour of their head, by the 
ash colour of the upper part of their body, and 
by whitishness instead of yellow in the lower 
part of the body. The cole-tit has a shining 
glossy black head and throat; and the marsh-tit 
has a dull non-shining black head and chin. The 
cole-tit, besides feeding on the same sorts of food 
as the tom-tit, though not so omnivorously, is 
very fond of pine seeds, and on this account 
abounds most in pine and fir forests and planta- 
tions; and it is the only species of tit which 
builds in holes on the ground, in preference to 
holes in trees and walls. The marsh-tit is per- 
haps more common in this country than the 
cole-tit; and a family of them may often be seen 
in the autumn attacking the ripe seeds of a sun- 
SS SS ae 
