134 LECTURE XI. 



caeca. The middle part of the eleventh division extends backwards, 

 in the form of a small funnel-shaped process, and opens into the 

 commencement of the slender intestinal canal (f/, d) ; this is situated 

 between the two last and longest gastric caeca (^c) ; it terminates by a 

 small anus (e) above the terminal sucker.* 



There is a whitish glandular stratum in the coats of the oesophagus, 

 representing the salivary system. A peculiar brown tissue extends 

 along the alimentary canal between the nervous chord and the mucous 

 glands, and also upon the dorsal aspect of the anterior part of the 

 cavity. It is composed of a congeries of elongated, convoluted, and 

 irregularly constricted follicles, which are united in groups by the 

 confluence of their ducts into a single slender excretory tube. These 

 tubes unite with those of other groups of the follicles, and pour a 

 secretion, analogous to bile, into the posterior divisions of the stomach 

 and into the intestine. The confluence of the hepatic ducts is very 

 remarkable and conspicuous when they lie upon the testes, f 



The mouth is furnished in the earth-worm with a short proboscis, 

 but is without teeth : the decaying parts of animals and vegetables 

 are swallowed with the soil, and conveyed by a short and wide oeso- 

 phagus to a muscular compartment of the digestive canal, analogous 

 to a gizzard. The oesophagus is sometimes dilated, like a crop, above 

 this part. The long and wide intestine is continued straight to the 

 terminal vent, and is constricted in its course by the transverse septa 

 of the common cavity of the body ; but the sacculi are not produced 

 into caeca.:}: It contains along and slender blind tube, called the 

 typhlosole, attached to the inner surface, in which the chyle is strained 

 off" from the coarse contents of the wider intestine. 



The obliquity of the constrictions of the alimentary canal in the 

 Sabella pavoniiia § give it the appearance of being a long and narrow 

 tube disposed in a series of close spiral coils ; but it is merely saccu- 

 lated. In most other tubicolar anellides the intestine is less constricted 

 than in the Sabella. 



In the TerehellcB nebulosa and conchilega the wide oesophagus is 

 separated from the slightly sacculated gastro-intestinal tube by a con- 

 striction, which lodges an annular vessel. In the Hermella there is a 

 short oval dilatation or stomach between the oesophagus and intestine. 



In the sand -worm (Are?iicola) the gastro-intestinal canal (Jig- 73.) 

 commences at the termination of the oesophagus (b) by a sudden 

 dilatation, into which two caecal glandular pouches (c) pour their 

 secretion : the rest of the canal is simple in its outward form ; but 



* See Preps. Nos. 442. 466, 467, 468, 569. 595. A. 



f Brandt, Medizin Zoologic, Bd. ii. 



i Prep. No. 595. B. § No. 441 . 



