OXYURIS VERMICULAR1S. 



359 



yet been discovered, but can scarcely exceed the size of a visible 

 point. They will be recognised by their obtuse anterior and 

 posterior extremities. 



From Wedl's description it appears that he saw the first and 

 second forms. All the three forms occur abundantly together in 

 one and the same intestine. 



The skin, head, oesophagus, and intestine are similar in both 

 sexes, of course with the exception of the comparative size. 



The nervous system of the Oxyurides is, according to Walter 

 extraordinarily developed, but has hitherto Fl &- 2> 



been entirely overlooked. According to 

 him, the nervous system of Oxyuris 

 ornata is as well developed as in Mermis, l 

 except that a separate intestinal nervous i 



system is wanting. We have in the 

 Oxyurides a central (cerebral and caudal 

 ganglia) and a peripheric nervous septum. 

 The brain = the cephalic ganglionic mass, 7fnrSi,i!J'l 



in O. ornata is an aggregation of large q fffijp 



ganglia destitute of a membrane, on the rto 



sides and in the middle of the oesophagus, 

 and an aggregation of smaller ganglionic 

 masses lying transversely under the brain. 

 The latter sends out filaments on each side 

 to the oesophagus, and upwards and down- 

 wards to the lateral ganglionic masses ; ^ 

 the former to the muscles and fat- 

 canals (Fettschlauchen) to the mouth and 

 the four ridges of corium, in which they 

 distribute themselves in fine ramifica- 

 tions (organs of sense), and downwards 

 on each side a broad cord transverselv 

 inwards on the back of the oesophagus, 

 where the two branches unite, and 

 together with the ganglia form the 

 oesophageal ring. From this ring, rami- 

 fications pass to the lowest parts of 

 the lateral ganglia, transverse branches 

 to the muscles and fat-canals, and a 



Fig. 2. Young female of Oxyuris ornata, in which the generative organs are unde- 

 veloped, viewed from the ventral surface; magnified 176 times, n. Oral aperture with 



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