Mar. is, 1925 Cooperia Bisonis , a New Mematode from the Buffalo 573 
end of the body. It has chitinous 
lips protruding obliquely to the axes 
of the body; it is covered by a large 
projecting linguiform process 166 to 
177 p in length, extending backward. 
The width of the body shows a marked 
increase just anterior to the vulva, 
being 157 to 257 p at this point; pos¬ 
terior to the vulva is a sharp diminu¬ 
tion in diameter, it being only 91 to 
116 m wide. The combined length of 
the muscular ovejectors, including the 
sphincters, is 532 to 747 p. The eggs 
appear strikingly large in proportion 
to the width of the worm; they are 91 
to 99 p long by 41 to 49 p wide and are 
in the morula stage of development 
when they reach the vulva. The anus 
(fig. 7) is situated 174 to 190 p from the 
posterior extremity. The body gradu¬ 
ally narrows posterior to the anus to 
form a delicately pointed tail bearing 
at its tip a small bulbous swelling. 
Toward the extremity the transverse 
striations of the cuticle are deeper than 
elsewhere, giving the appearance of 
pseudo-annulations. 
o/mm 
Fig. 6 — Cooperia bisonis. Vulva region of female 
Host.—Bison bison. 
Location .—Fourth stomach and duo¬ 
denum. 
Locality. —Wainwright, Alberta, 
Canada. 
Type material .—Bureau of Animal 
Industry, Helminthological Collection, 
No. 25516. 
Cooperia bisonis is most closely related 
to C. oncophora, 
but differs from it 
in showing a more 
marked thickening 
of the body in the 
region of the vulva; 
in the vulva and 
anus being some¬ 
what farther from 
the posterior end of 
the body; in thelarge 
linguiform process 
overlapping the vul¬ 
va; in the larger size 
of the eggs, and in 
the ventral branches 
of the dorsal rays 
originating near the 
j unction of the latter 
with the stem,rather 
than from the 
middle of them. 
The size of the eggs 
of C. bisonis (91 to 
99 jj.) exceeds that 
given in the generic 
description (60 to 80 
p ), so that the latter 
will have to be 
modified to include 
this species. 
The points of 
distinction of the 
five species of Coop¬ 
eria found in rumin 
the following key: 
Fig. 7 — Cooperia bi¬ 
sonis. Posterior ex¬ 
tremity of female 
its are covered in 
1. Total length of dorsal ray 70 to 75 y; spicules 
of male less than 200 y long; vulva of fe¬ 
male situated not more than 1.5 mm. 
from posterior end of body__ 2 
Total length of dorsal ray 180 y or more; 
spicules more then 200 y long; vulva 
situated 1.6 mm. or more from posterior 
end of body__ 8 
2. Branches of dorsal ray curved in shape of a 
lyre; combined length of muscular 
ovejectors 375 to 560 y\ chitinous lips of 
vulva elongated transversely_ C. curticei 
Branches of dorsal ray nearly straight and 
parallel; combined length of muscular 
ovejectors 250 to 275 y\ chitinous lips of 
vulva elongated longitudinally.. C. punct at a 
3. Vulva covered by a large projecting lingui¬ 
form process; eggs 91 to 99 y long by 41 to 
49 y wide; spicules 224 to 240 y long.. C. bisonis 
Vulva not covered by a large projecting 
linguiform process; eggs 60 to 80 y long 
by 30 to 36 y wide; spicules 240 to 300 y 
long___ 4 
4. Total length of dorsal ray 220-400 y\ 
branches of dorsal ray horse-shoe or U- 
shaped, with cleft tips; combined length 
of muscular ovejectors 700 y . C. oncophora 
Total length of dorsal ray 180 y; branches 
of dorsal ray close together, parallel 
and uncleft; combined length of muscu¬ 
lar ovejectors 300 y _ C. pectinata 
