24 THOMPSON YATES LABORATORIES REPORT 
This plan will be followed as nearly as possible in the following descriptions : — 
Filaria cypseli. Nov. Sp. 
Definitive host — Cypselus ajfinis. The West African swift. The infected birds 
were found to have built their nests among the rafters supporting the verandah of the 
telegraph station of the African Direct Telegraph Company at Bonny, Southern 
Nigeria ; and in the neighbouring palm trees. 
Site. The adult filariae were found in the subcutaneous tissues of the head and 
neck. In one bird six worms occurred, lour of which were mature females, one an 
immature female, and the sixth a mature male ; in another two females and one male. 
Some came off with the skin on stripping the scalp ; two were found in the neck, one 
of them extending as far down as the middle of the back. They were not coiled up 
but lay more or less straight among the subcutaneous tissues. They were observed 
to move in the tissue with a slow sinuous motion backwards and forwards, and could 
be kept alive in normal salt solution for about ten hours. 
The adult worms are very long and thin, white in colour. The cuticle shows 
faint transverse striations. The female has an average length of 25*3 mm. — the 
length varying in our specimens from 24^0 to 26*7 mm. (the immature female 
measured only 16 mm. long). The breadth of the body is o - 22 mm. 
r . r , '•■ r~ 0-54, 17, 2 "5> ** 
Lobb s formula is : 
-, o-8, 0:88, 0-84, o-8, 
The head end [plate I, fig. 2] is somewhat bulbous, and has the shape of a 
short cone slightly flattened at the apex — which is the position of the oral orifice. 
On the rim of the slightly flattened area are four minute papillae. The oral orifice 
is placed centrally — no buccal appendages can be made out. The buccal cavity is 
continued backwards into a thick-walled narrow-lumened oesophagus, which is 0*45 
mm. long, bulbous posteriorly, and distinctly marked off by a constriction from 
the rest of the alimentary tract. What appears to be the nerve collar or commissure 
crosses the oesophagus at a distance of about one quarter of its length from the 
anterior end. The gut is continued almost straight down the length of the worm, 
curving only from side to side, and ending at the terminally placed anus. The 
position of the anal orifice is indicated by a depression placed slightly subterminally. 
The tail end does not taper, but is slightly swollen at the extreme end, which is very 
abruptly rounded off. (Plate I, fig. 3). The vaginal orifice is situated at a distance of 
07 mm. from the anterior end, and is placed at the centre of a small conical papilla. 
Two minute pre- and two post-vaginal spines can be made out (there may be six in all). 
The vagina which has thick muscular walls is directed generally backwards, but accord- 
ing to the state of engorgement of the uterus it may first go a little backwards and then 
* t denotes that the position of the anus is terminal. 
