582 ORGANS OF SECRETION. 



into the mouth near the masticating apparatus. The male 

 and female genital glands have assumed a more complicated 

 form, and the exterior secreting surface of the mantle pours 

 out the calcareous matter of their complicated shell, and the 

 dark coloured epidermis covering the peduncle of anatifee. 



Numerous small coeca, or biliary tubuli, are seen extending 

 from the periphery of the digestive canal of many annulida, 

 as the common earth-worm, which generally assume the 

 saccular form of dilated follicles, as the gastric follicles of 

 polygastrica, and are commonly filled with their yellowish- 

 white coloured bilious secretion. These tubuli are very short, 

 wide, and rudimentary along the sides of the stomach of the 

 leech, excepting the last pair, near the pyloric valve, which 

 have the narrow lengthened form of the hepatic tubuli of 

 insects. In halithea, they arise by narrow openings from 

 along the sides of the dorsal aspect of the stomach, they are 

 much elongated, slightly ramified, and enlarge at their ex- 

 tremities into vesicles generally filled with digested or 

 secreted matter. They are ramified also in planarise and 

 other annelides, as the prolongations of the stomach in many 

 of the parenchymatous entozoa. From the biliary tubuli, 

 such as they are, in the leech, extending along the entire 

 length of the stomach, and ceasing to be developed at the 

 pyloric valve, we more distinctly perceive the great extent of 

 the alimentary canal which here corresponds to the gastric 

 cavity of higher animals, and the relations of the hepatic 

 tubuli to that cavity. The higher development and greater 

 constancy of the salivary glands in annelides than in entozoa, 

 corresponds with the higher condition of their masticatory 

 and other organs, and the more mixed character of their 

 food. Several salivary follicles open into the mouth of the 

 earth-worm, as shown by Morren ; I have observed two 

 elongated salivary tubuli in the arenicola ; and Brandt found 

 them composed of clustered follicles in the leech. Besides 

 the internal chylopoietic, and the male and female generative 

 glands, we often find the naked surface of their body lubri- 

 cated by a copious, thick, viscid, mucous secretion poured 

 out from distinct glandular cutaneous orifices ; and this is 

 sometimes mixed with an acrid colouring matter, as we 

 observe in the deep yellow secretion thrown out from the 

 surface of the arenicola. Numerous distinct small round 



