No. 510] 



THE CUTICULA OF C EST ODES 



709 



exception of the Temnocephalidae) from their early larval 

 stages to those of the adult. 



But this is far from being the ease. The subcuticular 

 cells are wanting in probably the whole group of mono- 

 genetic trematodes, also in most of the Aspidobothridae 

 and in certain other digenetic trematodes. Goto (1894, 

 1899) has made a careful anatomical study of over forty 

 species of monogenetic trematodes belonging to some six- 

 teen genera, and has found no subcuticular cells in any 



of them (Fig. 4). He directed his attention specially to 

 the discovery of these cells in the worms studied by 

 Brandes, but says : 



Although I directed my special attention to the point. I have utterly 

 failed to observe those subcuticular cells so beautifully drawn by 



Cerfontaine (1899) has also made a study of some 

 twenty-eight species of monogenetic trematodes with the 

 same result (Fig. 5). 



It is true that peripheral single-celled glands are pres- 

 ent in probably all of these worms, the ducts of which can 

 be easily seen (Figs. 1 and 4) to pass not merely to but 

 through the cuticula to the outside surface of the body. 

 These gland cells are usually grouped at the forward end 



