164 MEDICAL ZOOLOGY. 



Oxyuris. Body subcylindrical, rather thick; caudal extremity acnte ; 

 head continuous with the body ; mouth terminal, naked, or papillose ; caudal 

 extremity of the male with a thorn-like process ; penis filiform, enclosed 

 within a tubular sheath ; female awl-shaped, with the genital pore at the an- 

 terior part of the body. Oviparous. (Diesing.) 



0. vermicularis, Bremser. Male : caudal extremity obtusely pointed ; 

 head truncated; mouth with three papillae; oesophagus triangular; penis 

 single, very small. Female : tail long, tnpering, terminating in three points. 

 Eggs oblong, asymmetrical, y^" in length, ^0,7" in diameter. The water 

 vascular system composed of four vessels one dorsal, one ventral, and one 

 on either side. 



Measurements. Male, " long; female, ^-" long. 



(Esophagus with thick muscular walls, dilates into a kind of crop at its 

 junction with the stomach ; the latter is short and globular. The com- 

 mencement of the intestine is enlarged, so that the alimentary canal has the 

 appearance of three stomachal dilatations. The intestine is nearly straight, 

 uns in the length of the animal, and preserves a uniform diameter up to the 

 rectum. It becomes enlarged at the posterior part of the body, forming a 

 short rectum, to again gradually narrow like the tail of which it fills the 

 cone. The anus, placed at the middle part of the base of the tail, is a trans- 

 verse slit. Development not known. 



Habitat. Large intestine. 



Sclerostoma. Body subcylindrical, attenuate at either end ; head sub- 

 globose ; mouth terminal, margin subcorneous, toothed or papillose. Male 

 caudal bursa entire or lobed, multiradiate ; penis enclosed in a bipartite 

 sheath. Female straight ; genital pore either in anterior or posterior part 

 of body. (Diesing.) 



S. duodenale, Cobbold. The oval papillae four in number asymmetrically 

 arranged, uneven, horny (probably chitinous), conical converging ; head 

 slightly pointed ; tail blunt, partially inflexed ; bursa cup-shaped, supported 

 by eleven chitinous rays ten simple, odd one bifurcated at summit. 



Female. Tail sharp, conical; genital orifice (?) ; oviparous; eggs (?). 

 Females more numerous than the males. 



Measurements. Male, " long; female, " long. 



Dracunculus. 



D. medinensis (Guinea-worm), Cobbold. 



Male unknown. Body terminating in a more or less curved, reversed 

 mucronate tail ; head somewhat truncate or flatly convex, with a simple 



