OXYURIS VEEMICULAKTS. 361 



stomach, unites with that of the other side to form the largest 

 peripheric stem in the ventral line between the intestine and fat- 

 canals; in the female this divides at the vaginal orifice, runs 

 round the latter, and then re-unites. Consequently, three peri- 

 pheric stems issue from the brain, the last-mentioned central one 

 and two lateral ones, which soon become unrecognisable. They 

 send off branches (which rarely anastomose), at right angles to the 

 muscles, fat-tubes and genitalia, especially the vagina. The 

 oesophagus, stomach, and intestine, receive branches from them 

 and the neighbouring ganglia. The whole of the nervous trunks 

 consist of longitudinal fibres placed at a greater or less distance 

 apart ; the transverse branches are produced by the union of a 

 small branchlet coming from above and below, and disappear on 

 entering the organ, in the form of small, homogeneous triangles, 

 without further division. Neurilemma and cellular bodies are 

 wanting on the ramifications of the nerves. Whether a dorsal 

 nervous cord exists is still a question. The ventral nervous cord, 

 by dividing at the dilatation of the intestine, before the com- 

 mencement of the rectum into two large, but very short trunks, 

 becomes converted into a large, pyriform, ganglionic mass, 

 covering the intestine, or even exceeding it the principal caudal 

 ganglion ; a transverse branch passing transversely therefrom over 

 the rectum, gives origin to the formation of a moderate anal ring. 

 Besides these nervous masses, two small globular ganglia lie 

 laterally near the anal orifice, and a large, reniform ganglion 

 transversely at the lower end of the anus, from which issue 

 downwards two strongly converging branches, formed by the union 

 of several filaments. Here also, lies the last fusiform ganglionic 

 mass, which, at the commencement of the tail sends numerous 

 fine, lateral filaments to neighbouring organs (muscles, fat- 

 canals, male genitalia), and tapers to a fine point, which, after 

 giving off numerous lateral branchlets disappears in the corium. 

 It was seen and described by some authors, as Goeze and 

 Dujardin, as a ligament, but has always been misunderstood, or 

 overlooked. 



Method of investigation. The cerebral ganglia are difficult to 

 find, as everything depends upon the arrangement of the mirror, 

 management of the light, &c. For this purpose the older males 



isolated ganglion with several nervous cords. [The woodcuts and description are from 

 Dr. George Walter's paper on the Anatomy and Physiology of Oxyuris ornata, in the 

 eighth volume of the ' Zeitschrift fiir Wissenschaftliche Zoologie,' 1857. TRANS.] 



