12 s. GOTO. 



the continued existence of the oriu'inal epidermis, l^esides, the 

 differentiation of the investing membrane into the true cuticle and the 

 subcuticle, and the negative ftict that, although I have directed my 

 special attention to the point, I have utterly failed to observe those 

 subcuticular glands so beautifully drawn by Brandes in his figures 

 in the very same genera that he describes, strongly incline me to the 

 view that the investing membrane of the ectoparasitic Trematodes is a 

 transformed epidermis. I have indeed observed some cells in the 

 ectoparenchyma which had the appearance of a gland (PL XXI, fig. 

 4), but I have not been able to find out any duct, and believe them to 

 be cells of the mesenchyma- and will therefore describe tliem under 

 that bead. From his statements on p. 5()5 {op. cil.), I gather that 

 Brandes regards the muscular fibres described by Poirier" in some 

 species of Distomum as the dacts of the subcuticular glands ; but 

 Poirier's figure in (juestion is so clearly drawn that I doubt whether 

 one is justified to put another interprebition on it unless he has studied 

 the very same species. In Brandes' figures the nmscular fibres and 

 the ducts of the subcuticular ghuids are distinguished by di Itèrent co- 

 lours, but according to my own experience it is very douljtful whether 

 such difference in colour reaction exists reall}^ in nature. Moreover tbe 

 ducts of the subcuticubu' uhinds are drawn s(j fine in Brandes' 

 figures that one would be tempted to regard them also as muscular fibres 

 if they were coloured alike; and for my own part I do so regard them. 

 In this connection it may be mentioned that on examining once a 

 series of sections of Hcxacoli/Ic (jro.sm which were somewhat oN^erstained, 

 the terminal poi'tions of the dorso- ventral muscular ßbres were so 

 deeply stained that they looked just like the efferent ducts of some 



1). Poirier— Contriljutiou à I'liistoirc naturelle des Trematodes. Archives dc Zool. expcr., 

 2. série., T. Ill, 1885. 



