Abstract
This species is found very commonly in the gizzard of Formosan domestic duck.
In shape it closly resembles Streptocara crassicauda (CREPLIN, 1829), as stated by SKRJABIN (1916). For this reason, I think that my species will be the same to Streptocara crassicauda.
The body of the worm is long, white, and filiform; the head with two simple lateral lips, each bearing a dentiform process and two small lateral papillae; behind the lips is a collarette with an dentate anterior margin: the cervical papillae are represented by large crescentic structure with five or six (rarely three) small teeth on the posterior concave face; behind the buccal cavity is a short vestibule with delicate walls; oesophagus long and cylindrical, devided into two portions.
Male: smaller than the female, 6.5-7mm. long and 0.17mm. thick at the middle of the body; posterior extremity conical, blunt, and spirally coiled once; caudal alae present, 0.255mm. long and 0.05mm. thick; four pairs of costiform preanal and five pairs of costiform postanal papillae; spicules very unequal, -left spicule, filiform, 0.238mm. long and 0.007mm. thick; right spicule, boatshaped, short but wider, 0.085mm. long and 0.034mm. thick.
Female: 14-18mm. long and 0.238-0.289mm. thick; posterior extremity rounded: anus subterminal; vulva a little behind the middle of the body.
Mature eggs small, elliptical, with a thin shell, 0.039mm. by 0.0195mm. in size, containing an embryo at deposition.
Host: Anas domestica L., Cairina moschata L., Bastard of duck (Anas domestica) and musk duck (Cairina moschata).
Location: musculature of gizzard.
