THE COMMON RED WORM OR OUR RIVERS. 
13 
and present a most beautiful appearance. The same excretory 
tubes may be found in the common earthworm ( Lnmbricus 
terrestris), and are there visible to the naked eye. These 
cilia are found in other parts of the body — the interior of the 
intestine is lined with them, and they are easily seen at the 
extremities of the body, in continuous movement when the 
Tubifex is under the microscope. 
We must now say a little more about the blood-vessels of 
oui’ worm Besides the long vessel which runs along the intes- 
tine, called the dorsal vessel, we find another placed below the 
intestine, of rather smaller proportions, also running through 
the whole length of the body. These two blood-vessels are 
connected by smaller ones, as seen in figs. 1 and 2 — a pair in 
each ring of the body ; in the seventh ring of the body, count- 
ing downwards from the cephalic or head-segment, we find the 
two hearts, which are merely enlarged lateral vessels (fig. 2 a 
and fig. 1 d). It is a most beautiful sight to see these little 
hearts contracting and expanding while they send the blood 
through the various ramifications of the blood-vessels. In the 
region of the reproductive organs (from the eighth to the six- 
teenth ring of the body), there is an interesting modification 
of the lateral vessels. They are connected by two vessels which 
run parallel with the great dorsal and ventral arteries, the ar- 
rangement of which will be best seen from the plan of the 
circulation given in our drawing (fig. 2). 
We must now say a word or two concerning the reproductive 
apparatus, which is very complicated, the male and female 
organs being, as we before said, united in the same individual. 
In the eighth ring of the body, underneath the intestine, there 
is a round semi-opaque mass (fig. 5 a) ; this is the male glan- 
dular organ, and at the proper season of the year it is full of the 
spermatic filaments, which are often found collected together in 
discs somewhat resembling the beautiful little Sun animalcule 
(fig. 8). At a certain period the case enclosing these “ Sper- 
matozoa ” bursts, and they float into the cavity of the body ; 
thence they pass into a pah- of ciliated tubes which are found 
coiled up in the tenth ring of the body (fig. 4 d and fig. 5 e). 
These little tubes, like the excretory tubes, have large trumpet- 
shaped mouths, and are lined with minute cilia, the arrangement 
of which is seen in fig. 11. The arrangement of the other or- 
gans of reproduction will be best seen in figs. 4 and 5. The 
ovaries (fig. 4 a), contain eggs in all stages of development, 
which pass from them into a large cavity where they are pro- 
bably fecundated, as we find the ciliary tubes likewise connected 
with this part of the body. At the time that the eggs are 
deposited they are enveloped in little gelatinous capsules, each 
containing two or three eggs (fig. 10). These little capsules 
