268 E. RAY LANKESTER, ON THE EARTHWORM. 
are exactly similar to those found in the yellow tissue sur- 
rounding the dorsal blood-vessel by the cesophagus, and 
they appear to perform the same offices. It is almost uni- 
versally admitted that this yellow tunic of the intestine 
should be considered as discharging the functions which are 
distributed to various organs in the higher animals, viz., 
those of the gall-bladder, the pancreas, and the gastric glands. 
And it may therefore be conveniently called the hepatic 
membrane. 
The very numerous blood-vessels which ramify in this 
portion of the digestive tube, and around which the develop- 
ment of the hepatic cells is greatest, is connected, of course, 
with the elimimation of nutriment from the contents, and it 
is probably in this part of the viscera that the chief amount 
of absorption takes place. 
The muscular coat of the intestine is very delicate, but 
exercises considerable force in the propulsion of food. The 
transverse septal muscles, which are intimately connected 
with the folds of the intestine, also assist in causing those 
movements of the digestive cavity by which the passage. of 
aliment is effected. 
Anus.—After passing through three hundred and fifty 
rings in a well-grown worm, or less, the alimentary canal 
terminates in the last segment of the body. The modifica- 
tions of the septal muscles, which by Morren were described 
as peculiar muscles of the anus, and the contractility of the 
muscular membranes of the intestine and of the integument, 
effect the discharge of the feeces. The ciliated epithelium of 
the mucous membrane may be best observed near the anal 
aperture, where it appears to have its greatest development. 
Recapitulation.—The digestive organs of the earthworm con- 
sist of a mouth, situated in the first anterior segment of the 
body ; of an oval muscular pharynx, extending to the eighth 
segment; of a narrow contractile cesophagus, expanding in 
the fifteenth or sixteenth ring into a muscular crop, followed 
by a hard fibrous ring occupying the seventeenth and 
eighteenth segments. The rest of the body is traversed by 
the intestine, a plicated, delicate, elastic tube, invested in a 
membrane of granular cells, and terminating in the last rmg 
of the body. Connected with the pharynx are three convo- 
luted bedies, considered as salivary organs, and attached to 
the cesophagus are three pairs of glands in the twelfth and 
thirteenth segments, the two posterior pairs of which secrete 
a milky fluid, probably to assist iligetion 
The food of the worm is such fegetable matter as is con- 
tained in the rich loamy soils which it selects for habitation. 
(Zo be continued.) 
