250 Larval Flukes from China 
Aspidogaster conchicola has been recorded from both Europe and America, 
so that this record will place it in the group of widely distributed species. 
Cercariaeum, mutabile has been described from the Occident (Cort. 1919), 
although from an entirely different host. Cercaria pekinensis and Tetracoiyle 
orientalis (larva of Cyathocotyle orientalis) have recently been described from 
North China (Faust, 1921 and 1922). Of the remaining 21 forms, all are 
probably new species. Fourteen of this number, which I have had an 
opportunity to study, are described in this paper. 
Cercaria plana nov. spec. 
(Plate XXI, Fig. 1.) 
This monostome larva, for which the name Cercaria plana is proposed, was 
found in two collections of Viviparus quadratics (Bens.) in the vicinity of 
Peking in 1921. The former material was secured at the canal gate near the 
East City Wall, while the latter was obtained in the North Lake of the Imperial 
City. The infection in each case was about 1 per cent. 
The cercaria is a flat delicate larva, easily bursting under pressure of a cover 
glass. It measures 0*25 x 0-12 mm., and has a tail slightly longer than the 
body. Both the body of the cercaria and the tail are covered with minute 
spines. The movement of the mature animal is sluggish. The dorsal surface 
of the body is irregularly mottled with brown, particularly in the region of the 
eyes. The worm is trioculate, but the cyclopean eye is much slower in develop¬ 
ment than the lateral pair. The oral sucker is small (25 /x in transverse diameter). 
Behind it there is a distinct pharynx (Fig. 1, ph). Posterior to the pharynx 
there is a typical tuning-fork-shaped gut, the caeca of which end some distance 
anterior to the excretory bladder. The bladder is a subspherical organ, with 
a thin wall and a small pore. Proceeding from it anteriad are a pair of collecting 
tubules which appear to unite just posterior to the median eye. They are 
completely filled with excretory granules. On account of the opacity produced 
by cyst granules throughout the body, the finer details of the excretory system 
were obscured. The genital anlagen are similar to those of Cercaria spatula 
(Faust, 1919: 341, Fig. 1). Lateral to the excretory bladder are the lateral 
locomotor organs, which are simple invaginated pockets with a median 
attenuate lip capable of acting as a holdfast. The cystogenous cells are small 
and numerous. They are densely packed with minute rhabditiform granules. 
Encystment is slow but regular, with the laying down of a mucoid wall around 
the larva before the tail is dropped. 
Cercaria plana develops in a large redia with conspicuous feet, a large 
spherical pharynx and an extensive gut filled with deep orange food particles. 
