WORMS 297 



they are arranged in four longitudinal lines, running along 

 the ventral side of the animal two lines on each side and 

 that in each line there is a point protruded from each of 

 the many rings of which the Worm's body is made up. 



In order to see a little more of these organs we must 

 sacrifice a Worm; having killed it, and divided the body 

 in the middle, I cut off, with sharp scissors, a small trans- 

 verse portion, say two or three rings, and press the frag- 

 ment between plates of glass. Now, with a higher 

 magnifying power, we discern in the midst of the trans- 

 lucent flesh the points in question. They are not, how- 

 ever, single; but each protrusile organ consists of a pair 

 of transparent, brittle, glassy rods, shaped like an italic /, 

 of which the recurved points are directed backward when 

 thrust out from the skin. 



The mode in which these assist the progression of the 

 Worm is well described by Professor Eymer Jones. "The 

 attenuated rings in the neighborhood of the mouth are first 

 insinuated between the particles of the earth, which, from 

 their conical shape, they penetrate like a sharp wedge; in 

 this position they are firmly retained by the numerous re- 

 curved spines appended to the different segments; the 

 hinder parts of the body are then drawn forward by a 

 longitudinal contraction of the whole animal a movement 

 which not only prepares the creature for advancing further 

 into the soil, but by swelling out the anterior segments 

 forcibly dilates the passage into which the head had been 

 already thrust: the spines upon the hinder rings then take 

 a firm hold upon the sides of the hole thus formed; and, 

 preventing any retrograde movement, the head is again 

 forced forward through the yielding mould; so that, by a 

 repetition of the process, the animal is able to advance with 



