776 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [58] 



Following are the measurements of a living specimen : 



Millimeters. 



Length 28.00 



Length of botbria 2. 00 



Breadth of botbria, middle 20 



Diameter of neck near head 16 



' Diameter of neck at base .- 32 



Diameter of constriction between neck and body 18 



Length of neck 7. 00 



Length of first distinct segments 03 



Breadth of first distinct segments 40 



Length of median segments 20 



Breadth of median segments GO 



Length of posterior segments 1.00 



Breadth of posterior segments 40 



Measurements of median and posterior segments were made with dif- 

 ficulty on account of the incessant and active movements of con- 

 traction and expansion of those parts. The bothria, likewise, were in 

 constant motion and exact measurements of them could not be 

 obtained. The measurements given above are, however, approxi- 

 mately correct. In the living worm in sea-water the bothria and 

 pedicels are yellowish white, the neck and head between the bothria, 

 bluish white, anterior segments yellowish white, remaining segments 

 yellowish white at center with bluish white border along each margin. 

 The bothria were exceedingly active and they changed their position 

 constantly. The ends of the bothria being free and the whole organ 

 turning easily on its pedicels as on a pivot, it is therefore possible for 

 an infinite number of positions to be assumed. While the resting 

 position of a bothriuin is that in which its long axis is parallel with the 

 axis of the body, it is occasionally thrown forward and turned so as to 

 lie across the top of the head at right angles to the longitudinal axis 

 of the head. The ends of the bothria sometimes turn towards eachother, 

 sometimes they are reflexed. These movements and the resulting posi- 

 tions are all exceedingly graceful. The diameter of a pedicel, although 

 variable in life, is about, .36 mm and the thickness of abothrium near the 

 pedicel about the same, .36 mm . When one of the specimens was put in 

 fresh water the bothria became arcuate, their ends being reflexed, while 

 the margins of the boat-shaped faces were closely appressed. The epi- 

 dermis of the body also became loosened and in places was detached. 



In fresh water and in alcohol the head and neck contract but little 

 while the body contracts very much. In the alcoholic specimens the 

 ends of the bothria are flexed so that the head is nearly globular. 



The long, cylindrical neck of the living worm, when viewed with 

 transmitted light, was seen to be traversed by a dark central line and 

 by many wavy or crinkled longitudinal fibers. When moderately mag- 

 nified, the dark central line appeared to lie between two inclosing dark 

 lines, as if in a tube. The neck, while very flexible and often changing 

 its position, was not observed to contract or expand. 



One of the specimens has a crenulated marginal outline to the pos- 



