362 ANIMAL PARASITES. 



are best fitted ; they are to be cut through in the region of the 

 stomach. The animals should be examined as fresh as possible, 

 without water, rather with the application of turpentine. The 

 caudal ganglia are best found in young females, after the animal 

 has been cut through above the caudal ganglia, and the uterus 

 with its eggs has been removed. The sarcode globules in the 

 penis and its muscles in the male, readily obscure the investiga- 

 tion in that sex. The peripheric nerves, especially their trans- 

 verse branches, are more easily detected, especially in animals 

 which have been cut through and deprived of their contents. 



As regards the form of the ganglionic cells, unipolar cells 

 with large nucleoli are seen, especially in the pyriform ganglion, 

 in the ganglion placed about the lower margin of the rectum, and 

 the middle of the cerebral ganglion; bipolar cells, which are 

 longer and narrower, are seen on the margin of the cerebral 

 ganglion, and in the fusiform ganglion, which is entirely com- 

 posed of them. Apolar cells are wanting, as are also multipolar 

 cells, of which, however, a few may, perhaps, occur in males, on 

 each side of the pyriform caudal ganglion. The bipolar cells 

 consist of a delicate membrane with finely granular contents and 

 a nucleolus, sometimes double, with a delicate outline, usually 

 situated in the middle. 



The primitive nervous filaments are produced from the pro- 

 cesses of the ganglionic cells (which are particularly visible on 

 the marginal ganglion of the brain, and in the fusiform caudal 

 ganglion) ; by the union of several primitive filaments of this 

 kind, narrower or broader branches are produced (these are 

 particularly visible on the upper and lower cerebral ganglionic 

 masses). 



I have unfortunately not succeeded hitherto in detecting the 

 nervous cords in Oxyuris vermicularis. 



The following is an abstract of the characters as they are 

 given in Walter's beautiful investigations upon Oxyuris ornata 

 (Siebold and Kolliker's ' Zeitschr./ viii, pp. 163 201, tab. v. 

 -vi). 



The skin of the Oxyurides consists, according to Walter, 

 of an external layer of epidermis, and beneath this, a delicate but 

 densely fibrous corium. 



The epidermis, in young individuals, forms a delicate boundary 

 line, which does not separate in water, but is not, as in Mermis, 

 composed of hexagonal cells but simply by exudation. At the 



