II. 
THE FILARIAE 
These will be described in a subsequent chapter. 
The genus Filaria is a very large one. It appears to be confined to 
vertebrates, usually living in the tissues of the body and not in the intestines. The 
worms are remarkable for their long slender bodies, which are almost of the same 
breadth throughout the whole length. The anterior extremity is rounded, and often 
has no lips. The males, which are markedly smaller than the females, have an 
incurved or spiral tail sometimes furnished with lateral expansions ; more often they 
possess four pre-anal, and a variable number of post-anal papillae ; the spicules vary 
considerably in size and appearance. In the females the vulva opens more or less 
near the mouth. 
Filaria which are Parasites of Man 
Filaria bancroftii 
Filaria diurna 
Filaria per starts 
Filaria ozzardi 
Filaria magalhesi 
Filaria demarquaii 
Filaria loa 
Filaria medinensis 
Guinea worm : The adult female is a white or yellowish worm, averaging 
about sixty centimetres long, though specimens reaching four metres in length 
have been described. Its breadth, which is uniform, is from 0*5 to 1*7 mm. 
The anterior extremity, which tapers slightly, is truncated, and presents a rugous 
cuticular thickening in the centre of which is the triangular buccal orifice. The 
thickening bears two large papillae, one dorsal and one ventral, and six small 
papillae. The body shows faint transverse striation. The cuticle is thick. The mus- 
culature is polymyarian. The tail incurved towards the ventral surface in the matured 
females, terminates in a sharply bent hook about 1 mm. in length. The alimentary 
canal consists of a fine tube running from the mouth to near the tail, but not opening 
externally in the gravid female, though an anal orifice exists in the young parasite. 
In the mature worm the uterus crowded with embryos fills the whole body cavity— 
vulval opening and vagina being obliterated. The embryos, usually lying curved on 
themselves in utero, measure 15 to 25 /u long by o^o-o^o m wide. They are 
slightly flattened, transversely striated, and provided with a finely tapering tail which 
measures about two-fifths of their whole length. Thev have a rudiment of an 
