90 American Quarterly Microscopical Journal. 



at a point nearly opposite. Examined after death it is nearly 

 always found protruding. It is easily seen with a i-in. object- 

 ive, and studied profitably with a |^-inch. 



Has our distome a nervous system — any special sense ? 

 The demonstration of anything like a nervous system has 

 entirely failed in our hands. It was supposed that the pig- 

 mentary spots just below the cephalic sucker represented at T 

 were eyes, but most authorities hold to the opinion that they 

 are simply an aggregation of pigment cells. 



The digestive apparatus is exceedingly simple. The food 

 enters the mouth at the base of the cephalic sucker, and, 

 passing through the pharynx and oesophagus, enters the blind 

 intestinal tubes. 



The circulation of a colorless fluid containing granules, ap- 

 pears to be due to the general contractions of the body and walls 

 of the vessels, yet one is surprised at the regularity of the 

 oscillations. A complete oscillation occupied seven seconds. 

 This was true at one examination for eleven consecutive oscil- 

 lations. The oscillations were not so regular in all cases. 

 Some specimens did not present them at all, while the time in 

 others varied for each oscillation from four to thirteen seconds. 



Fig. 2 represents the posterior sucker magnified looo 

 diameters and reduced. We see two sets of fibers covering 

 the body, the one longitudinal and the other circular. These 

 are very intimately blended in some parts of the body ; when 

 not so, the circular fibers constitute the outer layer. Around 

 the border we notice the longitudinal fibers, showing their 

 nuclei very distinctly {C). 



Toward the bottom of the sucker the circular fibers are 

 greatly in excess {E). The center looks perforated, but the 

 dark color is due to the close and compact fibers stained here 

 with carmine. This center is never seen to open and close as 

 does a similar point in the cephalic sucker. Neither are 

 foreign bodies ever seen to enter it. At this point it is im- 

 perforate, and owes its appearance to the mechanism of its 

 fibers. The peculiar arrangement of fibers at F is very strange 

 and difficult to describe. At the right is a diagrammatic section 

 of these fibers. They are bundles of smooth muscle-fibers 

 with one end {B) attached at the bottom of the sucker, 

 while the other terminates in a free, rounded, blunt point. 

 They appear to lie beneath the two sets of fibers composing 



