576 Notices of Irish Eidozoa. 



its native home the head is lodged in one of the pyloric cceca, 

 to the walls of which it adheres by using one or more of its 

 bothria as a sucker; and I have repeatedly seen it attach it- 

 self in this way to the bottom of a dish so firmly, that the an- 

 terior third of the body could be pulled out to the fineness of 

 a hair before it would let go its hold. When placed on a slip 

 of glass and examined in the microscope, it appears to me in 

 the first place to expand its lower fovea or bothrium on the 

 surface of the glass, so as to act as a sucker ; it then contracts 

 the head and cervical joints, by which the anterior part of 

 the body is drawn forward ; it then loosens its hold, pushes 

 out the head to its utmost extent, becomes fastened to the 

 glass as before, and again contracts or shortens the anterior 

 articulations, and by a continued repetition of this action it 

 advances forwards, longing, no doubt, for what it will never 

 reach, — a safe lodgement in its old habitation. Thus the 

 head assumes, in its various states of contraction, every in- 

 termediate form from long and linear, when it is fully stretch- 

 ed out, to broad and heart-shaped, when it is fully contracted. 



From long and patient examination of this species in the 

 microscope, I am almost fully satisfied that it has four both- 

 ria, and not two only, as has been supposed. While the low- 

 er one has been expanded on the glass, and I was pretty cer- 

 tain of two lateral ones besides, I have seen the top of the 

 head to open almost from end to end, leaving a transparent 

 space in the middle, remaining thus for a considerable time, 

 or opening and shutting at short intervals, the edges of the 

 linear cavity being quite distinct, though when the opening 

 was closed no line or mark was perceptible, to indicate that 

 there could be anything of the kind. 



This species, when taken from a fish not long out of wa- 

 ter, is often almost pellucid ; but placed in fresh water it 

 soon becomes very opaque and white, increases in breadth 

 and thickness, and soon appears to be dead. In the salt so- 

 lution mentioned in my last, it in a great measure retains its 

 pellucidity, and will continue alive forty-eight hours, or long- 

 er.* In the salt solution, too, it has a great tendency to twist 

 in spires, like a cork-screw, which I have observed also when 

 alive and vigorous in the intestinal mucus ; on this account, 

 when many are put together in the salt solution they get so 

 entangled that is very difficult to separate any one from the 



* On Saturday, the 5th of August last, I placed a number of specimens 

 from a Cotlus bubalis, caught on the morning of the same day, in the salt 

 solution ; and on the following Wednesday, though very languid, they were 

 still living. Others placed at the same time in fresh water, were motion- 

 less and apparently dead in less than two hours. 



