416 T. H. MOEGAN. 



deferentia are on the same segment. (It seems to me very 

 doubtful whether the surface line of the 4th metamere is due 

 to a half-metamere introduced.) 



In fig. 39, A,B,c, a compound, metamere occurs on the 15th 

 segment (15 — -ff). The opening of the right vasa deferentia 

 alone was visible on the exterior. The ovaries were found in 

 the 13th metamere. 



In fig. 40, A,B, we find a spiral involving the 8th, 9th, and 

 10th metameres, introducing an extra half-metamere on the 

 right side.^ The vasa deferentia open, nevertheless^ on the 

 same metamere (15th — 16th). Another modification starts 

 at the 15th metamere, and involves a few more posterior 

 segments. 



In fig. 41, A,B,c, we find four compound metameres (see c), 

 followed by a spiral that involves segments immediately in 

 front of the region of the opening of the vasa deferentia. 

 Fifteen half-metameres of the right side correspond to twenty 

 of the left side. The openings of the vasa deferentia appear 

 on the same ring, and this ring is made up of the 16th half- 

 metamere of one side and the 21st half-metamere of the 

 other. 



In fig.42, A,B,c, we find a compound metamere (3 — f), fol- 

 lowed by a complicated spiral (c) that involves the 14th to the 

 21st metameres. The openings of the vasa deferentia were not 

 seen on the outside. Unfortunately I have no records of the 

 dissection of this worm. 



In fig. 43, A, B, c, we find two spirals and a compound meta- 

 mere in the anterior region. The openings of the vasa de- 

 ferentia occur in the last spiral. The opening on the left side 

 is in the 18th half-metamere, and on the right side in the 16th 

 metamere. 



In fig. 44, A, B, a compound metamere (6 — f) is first 

 found, followed by a spiral belonging to category vii, PI. 40, 

 fig. VII, and this followed by another compound metamere 

 (X3 — ^|-). Three extra half-metameres arc introduced on 

 the right side. The openings of the vasa deferentia are 

 • Belongs to another category, i. e. D. 



