418 



ZOOLOGY 



SECT. 



of the ground or in the interior of its burrow. The setse in the 

 clitellum, and those in the neighbourhood of the genital apertures, 

 are much slenderer than the rest. Along the middle line of the 

 dorsal surface, from about the eleventh segment backwards, is a 

 row of small apertures, one at the line of division between each 

 contiguous pair of segments : these, which are termed the dorsal 

 pores, perforate the body- wall and open internally into the coelome. 

 On the ventral surface are two rows of minute apertures a pair 



B 



Fin. 3Js. Lumbricus aa ricola. A, entire specimen, lateral view ; B, ventral view of anterior 

 portion of the body, magnified. 1, 15, 33, first, fifteenth, and thirty-third segments. The 

 black dots represent the set. (After Vogt and Jung.) 



on each segment the excretory apertures or ncpliridioporcs. On 

 the ventral surface of the fifteenth segment (Fig. 328, 15}, is a 

 pair of slit-like apertures with somewhat tumid lips, the male 

 reproductive apertures ; and on the segment immediately in front, 

 the fourteenth, are two smaller rounded apertures, the female 

 reproductive apertures. In the intervals between the ninth and 

 tenth, and tenth and eleventh segments are two pairs of small 

 pores, the openings of the rceeptacula sc minis. 



