WORMS. 13 



the earthworm, and the rings broader, though fewer in 

 number, and that no segments are altered, or, speaking 

 scientifically, differentiated to form a " saddle," though 

 the first two rings are greatly modified to form a dis- 

 tinct head. 



Fig. 3, taken from Turn bull's paper " On the Anat- 

 omy and Habits of Nereis Yirens." * shows the head 

 and a portion of the body. The first ring (Fig. 3, hd 1 ) 

 is provided with four eyes and two pairs of antennae. 

 One pair is short and slender (a 1), and the other 

 pair, which is also attached to the second ring, is 

 short and stout (a 2). Each of the second pair of 

 antennae (or palpi, as they are sometimes called) has a 

 small, rounded lobe at its end. The second segment 

 {lid '2) is larger than the first, and is sometimes called 

 the mouth-ring because it contains the mouth. The 

 skin of this ring is wrinkled longitudinally. This seg- 

 ment bears four pairs of delieate, unjointed antennae 

 (a 3-fl 6), which are arranged in pairs, the outer (a 4. 

 a 5) being short, and the inner (a 3. </ 6) the longest. 

 The animal carries these in front or on the sides of its 

 head to aid it in searching for food, and also to warn 

 it of the approach of danger. As in the earthworm, 

 the mouth opens into a pouch or proboscis, which can 

 be turned outwards and used for obtaining food. In 

 many alcoholic specimens this remains permanently 

 everted, showing two large, black, hook-like jaws, one 

 on either side. A number of little teeth may also be 

 seen, arranged in groups upon its inner surface, which 

 look like so many tiny black dots. 



* See Trans. Conn. Acad., Vol III., Part 2, p. 265. 



