738 PROCEEDINQS OF THE ACADEMY OF [Dec, 



die region," showing the longitudinal muscle, L.M., with the subepithelial 

 muscle fibrils above, running transversely. X 004. 



Fig. 38. — Part of a longitudinal section of the proboscis, from the "mid- 

 dle region," showing the subepithelial muscle fibrils in transverse section. 

 The outer flattened epithelium is extremely thin. X 1120. 



Fig. 39. — Part of a longitudinal section of the proboscis, from the " poster- 

 ior region." The outer epithelium, o.Ep., is composed of cells of consider- 

 able height, with abundant cytoplasm. The subepithelial muscle fibres, 

 Ep.m.f., are thickened in this region. X 1120. 



Fig. 40. — Cross section through the "middle region" of the proboscis, 

 showing both dorsal and ventral muscular crosses, Xcl., Xc. The lateral 

 nerves form a continuous plexus, n.p. The glandular ridge of the dorsal 

 surface is very prominent, Gl.R. X 330. 



Fig. 41. — Cross section through the " posterior region " of the proboscis, 

 some distance anterior to its termination. The proboscis nerves are again 

 separate, P.N. X 320. 



Fig. 42. — Small "rhynohocoel corpuscles." X 1120. 



Fig. 43. — Large cells from the fluid of the rhynchocoel, "rhynchocffil cor- 

 puscles." The two nuclei, N., are probably the result of amitosis. 

 X 1120. 



Fig. 44. — Portion of a cross section of the proboscis immediately poster- 

 ior to its insertion, showing the regular brick-shaped cells of the outer 

 epithelium, o. Ep. The subepithelial muscle fibrils are absent from this, the 

 most anterior, region. X 604. 



Plate XLIII, Fig. 45. — Portion of a cross section through the body wall, 

 showing the excretory duct of the left nephridium. Excel. X 128. 



Fig. 46. — Portion of a cross section of the body, showing the left lateral 

 blood vessel, L. V., with the adjacent nephridial main duct, Nph.D., and a 

 ductule, Nph.d. X 320. 



Fig. 47. — Portion of a cross section of the body, showing the right lateral 

 blood vessel, L. V., into which project two terminal bulbs of the nephridia, 

 T.B. The epithelium of the blood vessel is not continued around the ends 

 of the terminal bulbs. X 604. 



Fig. 48. — Cross section of an ovum infected with a stage of a parasite 

 older (?) than that shown in fig. (Jl. X 604. 



Fig. 49. — Cross section of one of the dorso-lateral blood vessels. X 604. 



Fig. 50. — Portion of a cross section through the anterior part of the 

 rhynchocoel, showing the dorsal blood vessel. The endothelium. End., of 

 the ventral wall of the vessel is very distinct, but that of the dorsal wall is 

 interrupted by the proliferation of blood-forming cells, Bl.f. C. X 604. 



Fig. 51. — Cro-ss section of the dorsal blood vessel after it has left the 

 rhynchocoel. A network of connective tissue cells, Cii.T.N., surrounds the 

 blood vessel. X 604. 



Fig. 52. — Cro.ss section of the oldest stage of an immature ovum, free in 

 the centre of the gonad. The thick outer, o. O.mb., and the thin inner, 

 i. O.mb., egg membranes are shown. X 604. 



Fig. 53. — Surface view of the gonad epithelium. X 604. 



Fig. 54. — Portion of a cross section through an ovary, containing only 

 young stages. O.j represent the youngest ova figured, O.j and 0.^ older 

 forms. X 240. 



Fig. 55. — Portion of a cross section of the body wall, showing a testis 

 duct, T.d., with an expanded distal portion, h. The longitudinal muscle 

 layers of the body wall are not indicated. X 320. 



Fig. 56. — Horizontal optical section of a portion of the posterior body 

 region. Drawn from life, showing gonads filled with ova between the 

 intestinal caeca. The large body, Par., in the middle gonad is the cyst of a 

 parasite. X 70. 



