268 
Cladorchis subtriquetrus Rud. 
to that of the small intestine, was in no way inflamed or otherwise 
pathologically altered. With them numerous oxyures were associated, 
of a species not yet determined. 
The largest of the eleven specimens and a smaller were, while still 
moving, subjected to marked pressure between plate glass, fixed, and 
cleared in glycerin. The thickness of the worms thus treated permitted 
a determination of the grosser features only, with nothing of the minute 
and little of the grosser arrangement of the reproductive organs. A few 
ova were observed in the largest specimen which was teased with 
needles, the material being used in the succeeding determinations. 
The second, flattened specimen was cut serially in the frontal plane. 
A third worm, which when entire measured 4-1 x 2-4 mm., was cut 
serially in the transverse plane. The specimens when fixed in 4 % 
formalin were not distorted or appreciably shrunken, but the third 
worm was reduced by the histological technique to 2-56 mm. in length, 
2-2 mm. in greatest width and 2-0 mm. in greatest vent.ro-dorsal diameter 
as measured in sections. From the histological series drawings were 
made with the use of the Edinger projection apparatus, and from 
these a reconstruction of the internal anatomy was made by the wax 
plate method, omitting only the intricately formed structures such 
as vitellaria, nervous system and excretory ducts. All measurements 
hereafter given, unless otherwise noted, are taken from this third 
(shrunken) worm. 
External Anatomy. 
The specimens measure 5-1—6-3 mm. long x 3-0—3-5 mm. broad and 
2-0—2-25 mm. dorso-ventrally. They are subcvlindrical, the greatest 
diameter lying at the anterior borders of the acetabulum. 
The posterior extremity is broadly rounded and moderately curved 
ventrally. The anterior extremity is more strongly directed ventrally 
so that the oral orifice points ventrally. The anterior extremity 
is broadly rounded and variably but never more than moderately 
attenuated, from which circumstance some specimens are pyriform 
and others subcylindrical. One specimen is exceptional; its anterior 
extremity tapers more than in any of the others and is recurved upon 
the body axis in the form of an inverted question mark. The margins 
of all are rounded and undefined; the dorsum is broadly convex, the 
caeca being often seen in fixed specimens with the naked eye and 
always with a handdens. The caeca appear as black bilateral areas 
posteriorly and dorsally and are sometimes traceable upwards to the 
