118 WORMS. 



CLASS V. VERMES. WORMS. 



ORDER I. INTESTINA. 



Naked simple animals, without limbs. 

 A. Found within other animals : without eyes. 



1. ASCARIS. Body round elastic, tapering: towards each 



end : head with 3 vesicles : intestines pellucid, white, 

 spiral. 



2. TRICHOCEPHALUS. Body round, elasic, variously 



twisted, much thicker in front and furnished w ith a 

 slender protrusile proboscis : tail long, capillary, 

 tapering to a fine point. 



3. FILARIA. Body round, filiform, of equal thickness, 



quite smooth : mouth dilated, with a roundish concave 

 lip. 



4. ECHITVORINCHUS. Body round : mouth with a cylin- 



drical retractile proboscis, crowned with hooked 

 prickles. 



5. FACIOLA. Body flattish, with an aperture or pore 



at the head, and generally another at a distance 

 beneath. 



6. TAENIA. Body flat, composed of numerous joints: 



head with 4 orifices for suction a little below the 

 mouth : mouth terminal, generally crowned with a 

 double series of retractile hook*. 



B. Not inhabiting the bodies of other animals. 

 a. Furnished with a lateral pore. 



7. LUMBRICUS. Body round, annulate, with generally a 



fleshy belt near the head, mostly rough with minute 

 concealed prickles placed longitudinally. 



8. SIPUNCULUS. Body round, elongated : m outh cylindri- 



cal, terminal, narrower than the body : aperture at 

 the side of the body, wart-like. 



9. PLANARIA. Body flattish, pointed behind, gelatinous,. 



with a double ventral pore, proceeding with a slow 

 and uniform motion : mouth terminal. 



10. HIRUDO. Body oblong, truncate at each end, cartila- 

 ginous, unarmed, moving by dilating the head and 

 tail and contracting itself into an arch. 



b. Without the lateral pore. 

 H.'LIKEUS. Body a little depressed, linear, smooth: 



mouth longitudinal, placed underneath. 

 12. GORDIUS, Body round, filiform, of equal thickness, 



smooth. 



