472 REPORT OF THE HARVARD AFRICAN EXPEDITION 
Male. From 24 mm. to 26 mm. in length with a maximum breadth of 
0.47 mm. near the middle. Bursa short, measuring 0.23 mm. long by 0.4 mm. 
wide. Ray formula similar to that of the genus Oesophagostomum; ventral 
rays cleft near their base and parallel. Externolateral and other lateral rays 
arise from a common trunk; the former diverges and its tip does not quite reach 
to the margin of the bursa, while the mediolateral and posterolateral rays are 
parallel, and extend to the margin of the bursa. The externodorsal rays, which 
are relatively slender, arise from a common trunk with the dorsal ray. The 
latter divides near its middle, and each branch bifurcates terminally. Spicules 
equal in length, filiform and unsheated. They measure 1.23 mm. in length, and 
their termini are without barbs. A slender, curved gubernaculum, about 0.10 mm. 
long, is present. 
Female. From 30 to 31 mm. in length, with maximum breadth in the pos- 
terior half of the body of 0.78 mm. Oesophagus 0.78 mm. long. Measurements 
of buecal cavity approximate those of the male. The posterior half of the body 
tapers conically, to terminate in a sharp mucronate tail. Anus opens about 
0.15 mm. from tip of the tail, and the vulva, which does not have salient lips, is 
situated about an equal distance anterior to the anus. Muscular vagina about 
0.28 mm. long. It bifureates into two more or less kidney-shaped chambers, that 
receive two convergent ovejectors, which are continuous with the parallel uteri. 
Eggs (in uterus) thin-shelled, measuring, on the average, 80u by 40u. 
Host. Colobus polykomos (‘‘ Black and white’? Colobus monkey). 
Location. Small intestine (?). 
Locality. Du River, Liberia. 
Type. Male and female, Cat. No. 8017, U.S.N.M., Helm. Coll. 
Paratypes. Cat. No. 8018, U.S.N.M., Helm. Coll. 
Nine female and seven male specimens of the parasite described above were 
found free in the lumen of the small intestine of the host, which, at the time of 
examination, had been dead for several hours. Cysts, the size of a pea, resembling 
those produced by Oesophagostomum were seen by Dr. Max Theiler, a member 
of the Expedition, on the walls of the caecum, but on dissection of one of these 
cysts no parasites were found. Because of the generic affinities of the worms, it 
seems not unlikely that the normal habitat of the parasite is in the large intestine 
and that, in the present case, postmortem migration had occurred (see also 
page 420). 
The characters described in the diagnosis cannot be reconciled with those 
of any known genus of the Strongyloidea. On the basis of the shape of the buccal 
cavity and the associated oral structures, the status of the parasite would seem 
to fall between the two chief subfamilies, the Strongylinae and the Tricho- 
neminae, but in other characteristics it exhibits affinities with the Oesophagosto- 
minae. The shape of the buccal cavity is closer to that of the Strongylinae, but 
the absence of a dorsal oesophageal gland prolonged as a ridge on the dorsal wall 
of the buccal capsule is more characteristic of the Trichoneminae. If it were not 
for the lack of a transverse ventral cervical groove and of any semblance of 
cephalic inflations, an affinity with the Oesophagostominae would be indicated, 
