26 
S. P. H. & M. H. S. No. 9960) was collected from the small intestine 
of a cow {Bos ). Sept. 28, 1906, at Phrapatoom, Siam. Xo 
difference has been noticed between the Philippine and the Siam 
specimens. 
EXTERNAL CHARACTERS. 
Size. — The specimens vaiy from 7.5 to 9.5 nnn. in length, and from 
4.5 to 5 mm. in maximum breadth; may flatten under pressure to 7 
mm. broad. 
CoLOE. — Alcohol specimens are of a grayish buff color. 
Form. — In form the fixed specimens are canoe shaped with an at- 
tenuated oral and a rounded caudal extremity. The body is divisi- 
ble into a posterior somewhat cylindrical portion, forming about 
one-fourth of the total length and an anterior somewhat lancet- 
shaped portion forming the remaining three- fourths. The posterior 
cylindrical portion is slightly flattened on its ventral aspect on which 
it bears the aperture of the acetabulum. The anterior three-fourths 
of the body is arched dorsally and excavated ventrally. The dorsum 
may show two longitudinal depressions just mediad of the intestinal 
ceca. In some of the specimens the lateral margins have curled 
ventrad in a scroll-like fashion, but it is possible to flatten the speci- 
mens without breaking the margins. 
Surface. — The surface of the rounded posterior portion is smooth ; 
that of the anterior portion is smooth dorsally (without spines or 
papillae), but ventrally it is provided with two sets of dissimilar 
papillae. One of these sets consists of numerous small papillae cover- 
ing a circumscribed, slightly depressed area around the base of the 
genital papilla ; when the genital papilla is not extruded, the genital 
pore is still in the center of a mammalike elevation (fig. 41), which 
is much larger than the circumgenital papilla} just mentioned, and 
which is separated (in sagittal sections) about 1 mm. from the oral 
margin. The other set of papillBe consists of large and quite promi- 
nent elevations arranged in parallel longitudinal rows, extending 
from about 2 to 2.5 mm. from the oral margin to the rounded caudal 
portion of the body: laterally they do not attain quite the margins of 
the body ; the papillae near the median line are the largest, those near 
the lateral margins are smaller; further, the most anterior and the 
most posterior of the papillae incline to a smaller size; in their ar- 
rangement the papilla of any given longitudinal row are situated 
more or less regularly to correspond to the spaces between the papillae 
of the next longitudinal row; as a result, they appear not only in 
longitudinal, but also in diagonal rows. 
The venter and dorsum meet laterally in fairly sharp margins. 
Genital pore . — As indicated above, the genital pore (figs. 31 and 
41) is ventromedian about 1 mm. from the oral margin, namely. 
