1905.] NATURAL SCIENCES OF PHILADELPHIA. 399 



Lumbricillus agilis, figs. 23 to 28. 



Fig. 23. — Tliree dorsal and a, one ventral setse. X 33.5. 



Fig. 24. — Outline of brain, from above. X 150. 



Fig. 2.5. — The two forms of ca?lomic corpuscles. X 335. 



Fig. 26. — A nephridium from life. X225. 



Fig. 27. — Dorsal view of one of the male genital ducts. Drawn from a 



living worm. X55. 

 Fig. 28. — A spermatheca showing communication with oesophagus above 



and external opening below. X HO. 



Monopylephorus parvus, figs. 29 to 34. 



Fig. 29. — A strongly bifid seta from the ventral bundle of VI; a, a shghtly 



forked one from a dorsal bundle; b, tips of three from the posterior 



region. X280. 

 Fig. 30. — Two coelomic corpuscles. X280. 

 Fig. 31. — Outline of the brain, from above. X 180. 

 Fig. 32. — Outline of both male genital ducts in situ, as seen from the ventral 



surface of the body. X 180. 

 Fig. 33. — A transverse section passing through the male pore. X 180. 



at, atria; b, genital bursa; dv, dorsal blood-vessel; in, intestine; n, 



nerve cord; p, prostate gland; ss, sperm sac; cf , common orifice of 



male ducts. 

 Fig. 34. — Outline of spermatheca. X280. 



