PORTER: TRICHONYMPHA. 61 
scattered irregularly, apparently without relation to the contractile cords 
of the body-wall. ‘The young, as we shall see later, are provided with 
a coat of abundant cilia uniformly distributed. 
The body-wall is not without further differentiation, for at regular 
intervals it is marked by darker lines, which have the appearance of 
thickenings of the wall, or of separate cord-like structures applied to 
its inner surface. These are really contractile cords, which arise at the 
knob-like structure of the anterior tip of the parasite where it joins the 
peduncle. These cords are usually grouped together at the anterior 
end of the body, so that a portion of the surface is quite bare of them 
(Plate 4, Fig. 51 a). They pass backward in a slightly spiral direction 
(lecotropic), leaving between one another equal spaces. As a rule, each 
cord can be traced to the posterior extremity of the animal, and thence 
back again on the opposite side of the animal to the anterior end ; but 
sometimes the cords apparently terminate in cup-like depressions in the 
body-wall, which resemble pock-marks, being outlined by coarse granu- 
lar protoplasmic rings (Fig. 51, ann.). The cords are frequently so 
superficial that in profile views of the animalcule they are seen to cause 
the surface to project in the form of ridges. In some individuals there 
is to be scen in the middle of the space between two successive cords 
another and much finer line (Plate 4, Figs. 47, 54) running parallel 
with them. This narrower line or cord is apparently embedded in a 
more or less clear homogeneous substance, while the larger cords are 
surrounded by coarse granular protoplasm. In other cases the larger 
cords occupy the clear areas, and midway between them are sharply 
marked lines of coarsely granular protoplasm, which stains more deeply 
than the rest of the protoplasm (Fig. 51). 
In living specimens these cords keep up an incessant undulatory 
motion, producing an effect which very closely resembles bands of 
vibrating cilia The body of the adult, however, is generally quite bare 
of cilia, but when it is ciliated, the cilia are, as I have said, seattered 
promiscuously over the body, irrespective of the contractile cords, 
The contents of the sac-like body are finely and rather uniformly 
granular, and not very thick or viscid, and there are appearances of 
vacuolation in them. 
The nucleus of Pyrsonympha is a large pear-shaped or sometimes 
oval body, generally situated at about one fourth or one third of the 
distance from the anterior or attached end to the posterior end, and its 
more pointed extremity is turned toward the attached end of the animal- 
cule. It always contains a nucleolus (Plate 4, Fig. 47, nil.) at its larger 
VOL. XXXI. — NO. 3. 2 
