352 ROXIE A. WEBER. 



V. 



EXPLANATION OF PLATE II. 

 Helodrilus caliginosus trapezoides. 

 Fused through one segment only with irregular masses between 



7. No. 02. f 



the separate edges of the united segment. 



8. No. 172. j 



9. No. 173, united through four segments. 



10. No. 70, united through four segments. 



n. A section through the anterior portion of No. 70, showing a single set of 

 cerebral ganglia (bg) and one of the ventral ganglia (nc). 



12. A more posterior section of the same monster showing two ventral ganglia. 

 I3a and b. No. 90. 



14. No. 93. Y AH show very limited connection. 



15. No. 2. 



