g4 S. GOTO. 



In the intestine of the second type, the epithelial cells are, as 

 already stated, all alike, and do not contain pigment granules. In 

 Tristomum and CalicotijU, they stain but slightly, and have seemed in 

 some cases to be more or less vacuolated. In Monocotijle Ijimae, on 

 the other hand, they contain numerous, deeply staining granules 

 which are to all intents and purposes exactly similar to the granules 

 found in the cavity of the intestine of the same worm. I therefore 

 believe them to be the products of (partial ?) digestion taken in by 

 the epithelial cells. 



But by means of what is this (partial ?) digestion carried on ? It 

 has already been mentioned that the cells are all alike in appearance, 

 and none of them present any glandular appearance. In some polyclads 

 {Planoceridae), Lang'^ has described two forms of cells in the intes- 

 tinal epithelium : those of the first form were elongated and cylindric- 

 al, and usually contained large, homogeneous, refractive granules 

 which stained but slightly and looked like fat-globules ; those of 

 the second form were more or less club-shaped, with the thickened end 

 turned towards the lumen of the intestine, and these contained, besides 

 an elongated nucleus, numerous granules which were very deeply 

 stained, and which distinguished themselves from those of the other 

 form of cells by their much smaller size and a regularly spherical 

 shape. The latter cells the above named author regards as secretory 

 cells, and the granules as the product of secretion. In Distomum 

 Westermani, again, Kerbert'^ found, besides the ordinary intestinal 

 cells, " kolbenfbrmige Gebilde " similar to those of the turbellarians, 

 which however he holds as nothing else than ordinary epithelial cells 

 whose shapes have been changed by the ingestion of food. In Sjiluj- 



I). Lang — I. c. p. 141. 



2). Kerberfc— Beitrag zvir Kenntniss der Treinatoden. Archiv. f. mik. Anatomie. Bd. 19, 

 1881. p. 552. 



