THE INTERMEDIARY HOST OF FILARIA CYPSELI 
4i 
Filaria cypseli. — The adult worms found on dissection of the infected swifts 
were in all respects similar to those found in Nigeria by the members of the Malaria 
Expedition, 1 their 'site' was also similar. 
Of the three swifts found infected on November r, parent worms were not found 
in the first bird examined. In another bird, one immature female and one male parent 
were found in the subcutaneous tissue behind the occiput ; they were not together, the 
former being coiled up by itself. In the third bird, one female parent was found 
coiled up under the subcranial tissue on the top of the head. In one of the two 
birds found infected on December 2, two females (one fully grown) and one male 
adult were found under the subcranial fascia, near the posterior corner of the right 
eye. All of the worms were found coiled up together. In the other bird parent 
worms were not found. It is very probable that many parent worms escaped 
detection. 
The Embryo (Fig. 1). — In one of the infected birds embryos were seen in the 
lymph taken from the subcutaneous tissue of the back. The embryo is described as 
follows in the Report of the Expedition to Nigeria 1 : — 
'The embryo in the fresh condition as seen in lymph and some blood prepara- 
tions was 84-7 /ul long. The breadth of the sheath of the embryo, 12-78 /n ; of the 
embryo itself inside its sheath, 7-9 When fresh, the embryos exhibited a slow 
sinuous progressive movement ; while inside the sheath they were much more active. 
The two ends of the worm continually moved about, so that the tips seemed always 
in contact with the inner surface of the bluntly conical end of the sheath — the ends 
never being observed retracted from the sheath. This movement of the extremities 
inside the sheath, which appears a little too short for the embryo, causes the embryo 
to be thrown into two curves. Ecdysis was not observed. Both extremities of the 
embryo are bluntly rounded. At the anterior extremity is a short stout conical 
papilla, from the apex of which projects a short thick spine which is always closely 
applied to the inner surface of the rounded end of the sheath. There is no prepuce, 
but a distinct ridge marks off the body from the papilla ; neither spine nor papilla 
was observed to be w'thdrawn. Under high powers a central line appears to run 
down from the papilla into the body. The anterior portion of the body of the embryo 
tapers very slightly. The contents are finely granular, a larger more refractile granule 
appearing at a point at about a quarter of the length from the posterior end. At 
this end the worm has a short, rather broad, highly refractile tubercle, which is always 
in contact with the sheath, and moves from side to side along the concavity of the 
end of the sheath. 
' In fixed and stained preparations, in all of which the embryo is found shrunk in 
I. Report of the Malaria Expedition to Nigeria (1900), Part II, Filariasis, Liverpool School of Tropical Medicine. 
