244 PROF. W. A. HASWELL : 



Fig. 30. Sphcerosyllis hystri.v, J . Outlines of transverse section showing' the position of 

 the ventral pedal glands. X 300. 

 31. Exogone fustifera. Outline? of proventriculus from stained and cleared 

 specimen, showing the anterior proventricular glands and their ducts, x 440. 



Plate 18. 



Fig. 3:2. Sphcerosyllis hystrix. Anterior region from the dorsal side. X 240. Seta? only 

 represented on one side. 



33. <S'. hystri.v. Parapodium and cirri, x 440. 



34. 8. hystrix. First (most dorsal) compound seta, x 1040. 



35. 8. hystrix. Anal cirri. 



36. Exogone verrugera. Ventral view of a portion of a stained and cleared specimen 



of a female with earl}' ova, to show the ventral pedal gland with its mass of 

 secretion. 



37. E. fustifera. Horizontal section of proventriculus, showing ducts of anterior 



proventricular glands. 



38. E. fustifera. Sagittal section in the region of the junction of the pharynx and 



proventriculus, showing anterior proventricular glands and ducts. 



39. E. fustifera. Muscle-columns as seen in horizontal sections of the lateral wall of 



the proventriculus. 



40. E. fustifera. Transverse section through outer ends of muscle-columns as seen in 



horizontal series. 



Figs. 41 & 42. E. fustifera. Corresponding parts of two successive longitudinal (hori- 

 zontal) sections of a male specimen showing a nephridium at the point where it 

 opens on the exterior, with the Bifurcation of the main duct to form two loops. 

 X440. 



Fig. 43. E. fustifera. General view of nephridium phis testis at an earlier stage than that 

 represented in Figs. 41 and 42. From a stained and cleared specimen, x 1040. 



44. E. fustifera. Segment of a male specimen in which the nephridia plus testes are 



far advanced in development, hut have not yet begun to unite mesially. As in 

 the following figure, the setas are merely indicated. 



45. E. fustifera. Semi-diagrammatic view of a segment of a ripe male with the 



median vesicle surrounded by a mass of sperms. 



46. Sphcei-osyllis hystrix. Ventral view of left portion of a segment with young 



ovum enclosed in its follicle (nephridium) and the ventral pedal gland with the 

 mass of secretion by means of which the egg becomes attached after it has been 

 discharged. 



47. 8. hystrix. From a section passing through the point of attachment of an embryo 



(on.) to the ventral surface with the plug of secretion by means of which the 

 attachment is maintained, x 440. 



All the figures refer to Exogone fustifera. 

 Fig. 48. Ventral view of two segments of female with early ova. From stained and cleared 

 specimen, x 440. 



49. View of a segment of a female in which the two ovisacs (nephridia) have become 



fused together across the middle line. Shows also the positions of the ventral 

 pedal glands and the zone of integumentary glands, x 440. 



50. Segment of a female with the two ova fully grown lying side by side in the 



common follicle or nephridial sac. X 440. 



51. Segment of a female with the two ova lying one in front of the other. From 



stained and cleared specimen, x 440. 



