46 OP THE PRINCIPAL WORMS 



rides, though its figure has little resemblance to 

 them. Still less caa it pertain to the class of the 

 taeniae, among which it is ranked by Pallas. 

 Jiloch and Goeze afterwards formed a particular 

 genus of these worms, immediately following that 

 of the ascarides.(15i.) 



§> XXXII. The form of our tricocephalus is 

 that of a spiral line,(153) and its largest part does 

 not surpass half a line in diameter. The external 

 surface presents an assemblage of small transverse 

 lines, like rings. 



Its length is from an incli and a quarter to two 

 inches. One part of the body terminates in a fila- 

 mentous elongation, as fine as a hair, and coiled 

 round in a very surprising manner. The other 

 part, turning in a spiral form, most commonly ter- 

 minates in a hook, broad and obtuse, and similar 

 to the pistil of the liliaceous flowers. From this 

 extremity the worm can put forth a sort of tube, en- 

 veloped in a sheath.(iri.3) 



Its extremity, terminating in this very fine fila- 

 mentous elongation, and one half longer than its 

 body, has been taken for the tail of the worm by 

 Roederer, Wagler and Wrish erg, [15-1;) and for 

 this cause has been called trichiiris. On the oth- 

 er \mm\ Pallas,{iCi5) Muller,{i56) and Goeze'ioY) 

 Lave demonstrated that this part is the real head 

 of the tricocephalus. (158) Werner has also con- 

 troverted the opinion of these three naturalists, but 

 liis arguments are too weak to prove it incor- 

 rect :(159) and we have reason to admit tlie licad 



