252 
Larval Flukes from China 
while the caudal tube is eight to ten times the body length. At the junction 
of bulbus and caudal tube there is a noticeable enlargement. The lateral ex¬ 
cretory tubule (excretory projection of Cort) has about the same bore as the 
caudal tubule and is about twice as long as the body. This lateral tubule 
connects proximally with the excretory bladder on the one hand and with the 
bulbus on the other. It is evident both from observation of the living worm 
and from examination of the preserved specimen that the main caudal tube 
as well as the lateral tubule serve as accessory excretory canals, since the main 
tube is hollow throughout its entire length and has been seen to extrude small 
excretory granules. The bulbus is filled with two kinds of secretory cells, con¬ 
sisting of a layer of large cells with coarse flocculent contents of a basophil 
nature lining the central lumen, and a second series of fine granular eosinophil 
cells loosely filling in the spaces between the integument and the first series. 
The function of these cells is not known. Neither in fully developed forms nor 
in younger stages has the body been found invaginated within the bulbus as 
described for C. yoshidae (Cort, 1920: 12) and other closely related forms. 
While the body of the larva differentiates late, the internal structure is 
more fully organised than in other described species of the group. In addition 
to the oral sucker (43 /x in transection) and ventral sucker (37 p, in transection), 
the pharynx is well developed and the caeca provided with muscular walls. 
Furthermore, the anlagen of the genital organs have become separated into 
groups, with an anterior group (ga-^) consisting of vitellaria and a median ovary 
and a posterior group {ga 2 ) which cannot be determined with certainty but 
probably represents the fundamental male anlagen. I have not been able to 
make out many details of the excretory system within the body of the worm. 
The bladder is spherical with a posterior pore and collecting tubules which 
arise from its anterior margin near the mid-line. 
The cercaria of this species develops from the germ-ball stage much more 
uniformly than does C. macrura Faust (1921 a , p. 16), for in this form the body 
and the appendages mature more nearly at the same time. In partially 
developed forms the caudal tube is only moderately long and performs only 
a slight, sluggish movement, while in the most mature specimens found it 
beats violently, propelling the worm at a considerable speed. It is apparent 
that C. macrura represents one line of development in which the tail organs 
mature long before the worm is expelled from the parthenita, while C. syringi- 
cauda represents a type with optimum synchrony of development. C. cali- 
forniensis occupies an intermediate position. (Cort and Nichols, 1920.) 
The cercaria develops in a simple redia which lacks ‘'feet,’ but has a 
pharynx and long sacculate gut. Differentiation of parts in the embryonic 
cercaria takes place early. Growth from this stage into the mature cercaria 
is conspicuous because of the tremendous increase in size. No encvstment of 
the body per sc seems possible, since the body is not provided with cysto- 
genous glands. However, there may be a stage later than those observed 
when the body is withdrawn into the bulbus and the glandular cells of that 
