E. C. Faust 
257 
Posterior to the bladder is a small central portion of protoplasm, the Island 
of Cort (Fig. 11,70), lateral to which a pair of tubules are found with connection 
to the bladder on the anterior side and common junction with the long median 
tubule of the tail on the posterior side. This caudal element forks with the furci 
and opens at the tip of each furcus. It is evidently an accessory tubule assisting 
in the conduction and expulsion rather than the original collection of excretory 
wastes. 
Additional information relative to the basic structure of the flame-cells 
and capillaries is found in the successive stages of development of the system 
in the cercaria. In the germ-ball (Fig. 7) one sees a single flame-cell at the 
anterior end of the tubule for each side of the body. 
As the germ-ball elongates (Fig. 8) the flame-cell and capillary are found to 
divide, providing the basic a + /3 grouping for the system. In the next stage 
(Fig. 9) the a and /? groups have each divided into three. Moreover, the posterior 
(outer) and anterior (inner) branches of the collecting system have divided 
but without complete separation, leaving a communicating trunk. In the 
next stage (Fig. 10) this common tubule has become minimised (ost of Fig. 11), 
the anterior portion of each of the anterior tubules has become fused with its 
mate and only the caudal portions of the collecting system remain immature. 
Finally, in the fully developed cercaria (Fig. 11) the complete picture is ex¬ 
pressed. 
With the analysis of the system, the question arises as to the relation of 
the system to the series previously worked out. A comparison (Faust, 1919: 
334) shows that it has the same primitive pattern as the cercaria of Schisto¬ 
soma japonicum (cp. Fig. 8 with Fig. 2 a of Cort, 1918), but with this difference 
obtaining, that the pattern in the cercaria of S. japonicum has remained 
primitive with only a total of 22 flame-cells to represent the formula a + P, 
whereas, in the case of C. leptoderma, remarkable modifications have been made 
and a trichotomy has been imposed twice on the system (cp. with C. pekinensis , 
a cystocercous form, Faust 1921: 210-211). Thus in this type the complete 
formula is (a) 2 + (/3) 2 , where the factor “3” is indicated for this particular 
species. The system in this species is an excellent example of divergent 
evolution. 
Cercarta styloeuccalis nov. spec. 
(Plate XXII, Fig. 12.) 
The xiphidiocercaria, for which the name Cercaria slylobuccalis is proposed, 
was obtained from 10 out of 13 specimens of Limnaea plicatula Bens., obtained 
from the grounds of The Live Oak Temple in the Western Hills, near Peking. 
The cercaria has a body ovate in form, measuring about 0-27 mm. in length 
by 0*15 mm. in width, and a tail slightly longer than the body. The body is 
covered with short acicular spines, which are replaced at regular intervals by 
longer spines of the same kind. The tail is aspinose. The body surrounds the 
tail at the junction of body and tail, and is provided with a pair of special 
