ORGANS OF DIGESTION. 341 



stomach two large (117- B. e.) and five small (117. B. f.) 

 elongated coeca arise, which appear like hepatic or glandular 

 follicles, and do not admit into their interior the larger undi- 

 vided portions of the food contained in the general gastric 

 cavity (117- B. d.) From the pylorus, the intestine continues 

 downwards, narrow and nearly straight, to terminate (117- 

 B. ff.) in the cloacal opening at the posterior end of the body, 

 close to the two fleshy peduncles. The whole alimentary 

 canal, from the mouth to near the anus, is narrow and cylin- 

 drical in the rotifer vulgaris, and follows a slightly winding 

 spiral course through the body, closely surrounded with large, 

 short, biliary follicles. At its rectal termination, however, 

 it suddenly enlarges to form a wide globular colon. The 

 same structure, nearly, is seen in the alimentary cavity of the 

 philodina roseola (Fig. 11 7. C.) where the maxillae (117- C. 

 a. a.) and their muscular apparatus (117- C. b.) and the two 

 pharyngeal sacs or glands (117- C. h.) are succeeded by a 

 narrow and straight oesophagus (117- C. c.) and intestine 

 (1 17. C. d.) The narrow intestine is closely surrounded by in- 

 numerable short straight biliary follicles (! 17. C. e. e.) or glan- 

 dular cceca, throughout its whole course from the oesophagus 

 (117.C. c.) to the short dilated colon (117. C./.) which opens 

 by its rectal orifice (l 17. C. g.} into the cloaca where the genital 

 organs also terminate, as in most of the higher articulata. 

 The lower part of the intestine is slightly curved upwards 

 upon itself, so as to lengthen its course, in the brachionus 

 urceolaris and pterodina patina. The stomach and the 

 whole alimentary canal of the rotiferous animalcules move 

 freely and loosely backwards and forwards, to a great extent 

 in the wide and ciliated cavity of the abdomen, during the 

 contractions of the long, slender, transparent muscles which 

 extend longitudinally from the anterior end of the body, 

 and the two glandular pharyngeal sacs of very variable form 

 accompany them in their motions to and fro. The whole 

 cavity of the abdomen, as well as the wide cavity of the 

 intestine, in these transparent and colourless animals, appear 

 generally as if distended with pure water, and vibratile cilia 

 appear to be in rapid action both on the mucous k and the 

 peritoneal coats of the alimentary canal. 



VIII. Cirrhopoda. The masticating and digestive appa- 

 ratus of the cirrhopods present the same close affinities to 



