58 HABITS OF WORMS. CHAP. II. 



ciently tender. They generally seized the 

 thin edge of a leaf with their mouths, between 

 the projecting upper and lower lip ; the 

 thick and strong pharynx being at the same 

 time, as Perrier remarks, pushed forward 

 within their bodies, so as to afford a point 

 of resistance for the upper lip. In the case 

 of broad flat objects they acted in a wholly 

 different manner. The pointed anterior 

 extremity of the body, after being brought 

 into contact with an object of this kind, was 

 drawn within the adjoining rings, so that it 

 appeared truncated and became as thick as 

 the rest of the body. This part could then 

 be seen to swell a little ; and this, I believe, 

 is due to the pharynx being pushed a little 

 forwards. Then by a slight withdrawal of 

 the pharynx or by its expansion, a vacuum 

 was produced beneath the truncated slimy 

 end of the body whilst in contact with the 

 object; and by this means the two adhered 

 firmly together.* That under these circum- 

 stances a vacuum was produced was plainly 



* Claparfede remarks (' Zeitschrift fur wissenschaft. Zoolog.' 

 B. 19, 18G9, p. 602) that the pharynx appears from its structure 

 to be adapted for suction. 



