LUMBRICUS. 201 
which a long thin wsephagus passes back to the thin-walled 
crop. Upon the cesophagus are three pairs of pouches, the 
two hinder pair being known as calciferous 
glands. The crop leads into the muscular 
gizzard, which has a small opening into the long zu/estine. 
A fold of the dorsal wall, called the zypAlosule, projects into 
the lumen of the intestine. The alimentary canal is held in 
position by a complete series of ¢ransverse septa dividing the 
coelom into compartments. Each septum has an aperture 
by which ccelomic fluid can pass from one segment to the 
other. 
Alimentary. 
Fig. 127.—TRANSVERSE SECTION OF AN EARTHWORM IN THE 
INTESTINAL REGION. (Semi-diagrammatic. ) 
Yellow Cells. Dorsal Pore. 
Ectoderm. ‘A Dorsal Blood-vessel. 
Cuticle. 
Circular 
Muscles, 
2 ae 
Setze. ae 
Longitudinal 4 1 k 
Muscles, eo} Wind ¥6 
aed 
Nerve Cord. Ventral Blood-vessel. 
Under the ectoderm is a layer of connective tissue 
beneath which lies a series of circular muscles, 
Inside this there is a longitudinal series. These 
function very much as in Avenicola. 
The ccelomic fluid is nutritive and the celom is spacious. 
The ccelomic wall covering the intestine is thickened into a 
mass of excretory yellow cells. The blood-vascular system 
Blood. 18 easy to see, for the blood (mainly respiratory) : 
Vaienian. 1 bright red from the presence of hemoglobin 
(cf Arenicola). There is a main dorsal vessel 
running forwards and a ventral backwards. These are con- 
nected by numerous civcudar vessels, of which six at the 
Muscular. 
