92 JOURNAL OF THE 



a slender pointed tail (Fig. 17). In this form it resembles what 

 are called ^'vinegar eels." In the head end we notice the exser- 

 tile spear, with its tri-lobed base, the long, slender, tortuons 

 channel of the anterior })art of the oesophagus, and the ellip- 

 soidal muscular bulb, the middle part. The lumen of the 

 alimentary canal can also be seen, and it opens at the beginning 

 of the hyaline space near the tail end. (See Fig. 17, Plate IV). 

 The embryo, and for a time the young larva, possesses a celhilar 

 matrix inside the body wall, except at the head and tail ends. 

 This soon develops numerous fat globules whicli are clustered 

 around the alimentary canal. 



The young worms, when ushered into life, find themselves 

 imprisoned by walls of plant tissue which formed at once the 

 prison-house and tomb of their parent. (See Fig. 37, Plate 

 VI). How to escape these bars is their first concern. Per- 

 chance fortune may favor them if the cyst is near the surface of 

 the gall so that a crack or partial decay of the tissues may liber- 

 ate them. When not thus favored there are sometimes two 

 courses open to them, more often only one. If the cyst opens 

 into any of the large channels of the vascular tissue of the root, 

 which is frequently the case, the larvae may make their exit 

 through these to other parts of the same root. In a majority of 

 instances the worm must face the only alternative of starvation, 

 and actually batter a hole in the wall through which it may 

 escape. Taking position, with the head end against a cell wall, 

 it thrusts forward the exsertile spear, which strikes the cellulose 

 wall forcibly, when it is drawn back and thrust out again. This 

 process is repeated until a hole is made through the wall large 

 enough to admit the body of the worm, into which it passes, 

 and by successively battering down the cell walls of the sur- 

 rounding tissues it makes its way to freedom on the outside of 

 the gall or to a fresh portion of the same root. 



Having escaped from its confinement, by one of these three 

 courses, it immediately selects an(>ther part of the root or a fresh 

 young rootlet for attack and places itself in i)osition foi' the 

 siege. Bringing into play its exsertile ram, it forcibly gains 



