458 Illinois State Laboratory of Natural History. 

 EXPLANATION OF PLATES. 



ABBREVIATIONS. 

 at., atrium. «. c, nerve cord. 



clit., clitelluin. pr. spermiducal gland. 



coel., coelom. p. v. L v., posterior ventral lateral 



vessel. 

 '/. I. v., dorsal lateral vessel. Sep., septum. 



(I. v., dorsal vessel. */>. ch., spermiducal chamber. 



(7- p., genital papilla. sp. <L, sperm-duct. 



g. 8., genital seta. *}>. th.., spermatheca. 



0- - s - (it > gland of genital seta. sp. 8., sperm-sac. 



I. v., lateral vessel. v. n., integumental vascular 



network. 



m., muscles. ». v., ventral vessel. 



m. v. J. v., median ventral lateral vessel. po., spermiducal pore. 



Plate XXXIX. 

 Embolocephalus multisetosus. 



Fig. 1. Anterior part. X.18. 

 Fig. 2. Sets, x 250. 



a and b, from ventral buudles. 



c, palmate seta from dorsal bundle. 



d, distal end of same. 



Fig. 3. Sections of sperm-duct. X 180. 



Rh izo clri lus lacteus . 

 Fig. 4. Seta-. X 250. 



a, ordinary uncinate seta. 



b, genital seta from IX. 



c, genital setse from XL 



Fig. 5. Transverse section through spermiducal chamber, x 70. 



Plate XL. 



Rhizodrilus lacteus. 



Fig. 6. Sagittal section through genital papilla, seta, and gland of IX., 



combined from several sections. X 180. 

 Fig. 7. Transverse section through spermathecae. x 70. 

 Fig. 8. Diagram of blood-vessels in VII-IX. 



Ilyodrilus coccineus. 



Fig. 9. Diagram of blood-vessels in V VIII., adapted from a figure by 

 Stole. 



Vermiculus pilosus. 



Fig. 10. Diagram of blood-vessels in IV VI, from a figure by Goodrich. 

 Those of VII-X are similar. 



