NOTES AND DESCRIPTIONS OF SOME PARASITIC HELMINTHS 473 
especially since the bursal ray formula is practically identical with, and the 
dental armature of the oesophagus resembles these structures in Ternidens, a 
typical genus of the Oesophagostominae. In view of these considerations, the 
writer has refrained from indicating the subfamily relation of Colobostrongylus. 
It seems, however, that the Oesophagostominae, as at present defined, constitute 
an artificial group, necessitating the allocation to other subfamilies of several gen- 
era (as Oesophagostomoides Schwartz, 1928) } whose characteristics show a close 
affinity with the type genus Oesophagostomum. 
Anoplocephala gorillae Nybelin, 1927 
The worms are of a buff-yellow color. The strobila increases gradually but 
uniformly in width from the scolex posteriorly, the most anterior segments 
being 2.32 mm. broad, and the ultimate segments 12 mm. or more broad. The 
longest strobila of the seven collected measures 46 mm. The posterior ex- 
remity terminates in such broad and narrow segments that it seems likely 
that segments are shed as soon as they become gravid. Consequently, the 
specimens in our possession are to be regarded only as fragments. Strobili- 
zation extends throughout the entire length of the organism; the largest of our 
specimens is constituted by more than a hundred segments. The scolex is large, 
2.3 mm. wide by 1.29 mm. in length, and is set off from the rest of the strobila 
by a deep groove fringed at its margins. The suckers are arranged in two 
pairs, on the dorsal and ventral surfaces respectively. They are directed an- 
teriorly and are covered superficially by a thin, annulated sheet of cuticle form- 
ing asort of hood that covers the suckers (Text Fig. 1). The suckers are 1.19 mm. 
in diameter, the muscular rims being 184u broad. They have no appendages. 
Segmentation commences immediately behind the neck. The earliest seg- 
ments are very narrow (about 0.090 mm.) and the rudiments of the developing 
genital system are visible in the fourth segment. The segments in which the 
male genitalia are fully developed measure 0.54 mm. in width. The posterior 
margins of the segments are fimbriated and overlie the anterior portion of suc- 
ceeding segments to the extent of nearly half the width of the segment. 
The muscular system is very strongly developed. Numerous fibers arising 
from the subcuticular nucleated zones traverse the entire thickness of the seg- 
ment. Bundles, to the number of more than a hundred, of coarse, longitudinal 
fibers are somewhat irregularly arranged in the medullary parenchyma, but, 
in the main, the bundles are disposed in two layers. The sheet of transverse 
muscle fibers separating the medullary and cortical zones of parenchymatous 
tissue is also strongly developed. Imbedded in the superficial strata of the 
cortical parenchyma are exceedingly large numbers of calcareous granules. In 
the material at hand, the excretory system cannot be followed accurately. In 
the anterior region of the strobila, longitudinal sections reveal two pairs of 
longitudinal thin-walled tubes lying side by side in the same plane but running 
very sinuous courses. In toto-mounts of specimens only a single pair of tubes 
1 Schwartz, B.: Two new Nematodes of the Family Strongylidae, parasitic in the intestine of 
Mammals. Proc. U. 8. Nat. Mus., Washington (1928), vol. LX XIII, art. 2, pp. 1-5. 
