Lymphatics and Enteric Epithelium of Amia Calva 2)11 



"function from the amphibia onwards as organs of taste, 

 while in fishes they probably serve as tactile organs." 

 (Weidersheim, Comp. Anat. of Vertebrates, p. 167). Farther 

 caudad the surface layer of cells gradually becomes columnar 

 with many interspersed beaker-cells. Some distance cephalad 

 of the pneumatic duct-opening the stratified is replaced by a 

 columnar epithelium. The transition between the two is quite 

 sudden there being scarcely any overlaping of the two epithe- 

 liums. From this point to within about 2 c. m. of the pylorus, 

 the epithelium is ciliated. Incidentall}^ it may be mentioned 

 here that ciliated epitheliums have been found in several other 

 regions of the body. In the air-bladder, ciliated cells were 

 found from one end of the organ to the other. The cells are 

 columnar but the cilia are somewhat longer than in the oeso- 

 phagus or stomach. The ciliary currents extend cephalad or 

 toward the opening of the pneumatic duct. The epithelium 

 of the nasal cavity is also ciliated ; the cells are of the same 

 general form as those of the air-bladder and stomach but the 

 cilia are much longer than in either of the last mentioned 

 organs. It is stated in the Cyclopaedia of Anat. and Physiol. 

 (Vol. I, p. 633), that according to Purkinje, Valentin and 

 Steinbuch, the presence of bile arrests the motion of cilia. 

 This is incorrect, in the present instance at least, for cilia were 

 found moving vigorously immediately after empt^'ing the chole- 

 cyst of its contents. Ciliated cells were found throughout 

 the whole length of the vesicle and its long convoluted duct. 

 The cilia are quite long and easily seen in both fresh and 

 hardened specimens. The currents induced by the cilia ex- 

 tend toward the opening of the duct. 



To form some idea of the rapidity with which foreign bodies 

 are carried along by cilia, a clot of blood was placed on the 

 oesophagus at the level of the pneumatic duct opening ; at the 

 end of five minutes the clot had been carried caudad a distance 

 of 4}'2 c. m. Farther caudad, the clot moved much more 

 slowly. At the caudal end of the cesophagus is a short region 

 occupied by rather short, broad follicles lined by columnar 

 ciliated cells ; the true gland cells are first met with some dis- 

 tance caudad of the pneumatic duct opening. 



