[35] ENTOZOA OF MARINE FISHES OF NEW ENGLAND. 487 



The bead of the living worm is very variable in shape. The bothria 

 are lateral and are united at the apex by their margins ; usually broader 

 than long, slightly emarginate on the posterior edge, with a raised and 

 thickened border. The neck is long, cylindrical, the narrowest part 

 about half way between the head and the contractile bulbs. There is 

 a constriction immediately behind the contractile bulbs, back of which 

 the neck swells into a nearly globular base. This rounded basal part 

 of the neck is sharply marked off from the body by a short, narrow 

 constriction. The body is without segments or transverse markings of 

 any kind for a distance equal to as much as six times the length of the 

 head and neck. . Strite then begin, which outline squarish segments. 

 The first segments are a little longer than broad; subsequently they 

 become much longer than broad, crowded with ova, and with the geni- 

 tal apertures marginal. The four proboscis sheaths are long and 

 thrown into spirals, the. coils of the spirals being dense or loose, as the 

 neck is contracted or not. The proboscides when everted are seen to be 

 very long and slender. They are closely beset with small hooks, which, 

 when highly magnified; are seen to be of several distinct shapes. The 

 prevailing shape of those near the end of the proboscis is slender, taper- 

 ing, somewhat irregular in outline, with an abruptly recurved short 

 point. Others have the same length, but differ in being broader, and 

 in having a curved, convex outline on the posterior edge. Others have 

 the same outline, but are very short. Others are slender, curved slightly 

 and pointed, but are without the abruptly recurved point. Some are 

 straight, others nearly straight, but bent slightly about the middle. 

 The hooks on the proboscides, moreover, are arranged in distinct series 

 of ternate groups. This arrangement could be plainly distinguished in 

 some places, while in others it was but faintly indicated, and, owing to 

 the extreme smallness of the hooks and their peculiar shape, it was im- 

 possible, from the specimens at my disposal, to determine the exact 

 number of series, or whether, indeed, all the hooks were arranged in 

 these ternate groups or not. Where most distinct there seem to be 

 four series of ternate hooks. The longer hooks stand nearly at right 

 angles to the axis of the proboscis, and are equal in length to about 

 one-third of the diameter of the proboscis. 



The following measurements are from an alcoholic specimen : 



Millimeters. 



Length of strobile 31. 00 



Length of bothria 0. 42 



Breadth of bothria 0. 34 



Length of head and neck 2. 00 



Length of proboscis sheath 1. 40 



Length of contractile bulbs 0. 29 



Breadth of contractile bulbs 0. 10 



Breadth of neck near head (lateral) i 0. 24 



Breadth of neck near middle (lateral) 0. 20 



Breadth of neck in front of basal bulb . 0. 34 



