1901.] NATURAL SCIENCES OF PHILADELPHIA. 737 



Fig. 22. — rart of a cross .section of the body through the oesophageal 

 region. The anterior end of tlie uephiidial main diut, NjiIlD., is shown, 

 and the large expanded \eutral blood connectives, V.bl.con., are very prom- 

 inent. X 70. 



Fig. 23. — Part of a cro«s section of the body immediately in front of the 

 beginning of the middle iutestine, showing the inner circular muscle layer, 

 i.O.M., and the dorsal and ventral nni.scular crosses, D.m.cr., V.m.cr., 

 between the inner and outer circular muscle layers. The much enlarged 

 upper and lower dorsal nerves, u.D.N., I.B.N., are very prominent. 

 X 70. 



Fig. 24. — Part of a cross section of the body of a male in the region of the 

 gonads. The plane of the section passes througli one of the intestinal cscoa, 

 I.Cae., and the narrower part of the testis. The duct of the right band 

 testis is shown, T.d. The sexual products of this individual are only partly 

 mature, most of the cells being in the spermatogonic stage, Spg. X 70. 



Fig. 25. — Part of a cross section of the body of a female in the region of 

 the gonads. The oldest ova, 0., are free in the centre, the youngest are 

 attached to the wall of the gonad. Two encj'sted parasitic bodies, Far., are 

 present in the left-hand ovary. X 70. 



Fig. 26. — Cross section through the posterior region of the body, showing 

 the simple end intestine, E.I., without lateral caeca, and the two dorso- 

 lateral blooil vessels, DL V., that have resulted from a forking of the dorsal 

 vessel. The gonads are absent from this region. X 70. 



Fig. 27. — Cross section through the junction of the caudicle with the body; 

 the upper part of the figure belongs to the body, the lower part to the cau- 

 dicle. The different character of the walls of the two parts is very evident. 

 The end intestine, -£'./., has a dorsal position, and is about to open into the 

 anus. 



Fig. 28. — Cross section through the caudicle, showing the caudicle wall 

 and the central blood lacuna, Bl.L. The great numbers of connective tissue 

 cells, Cii.T.N., actually present are, for the sake of clearness, only approx- 

 imately represented. X 320. 



Plate XLII, Fig. 29. — Portion of a cross section of the epithelium of the 

 median blood vessel. X 604. 



Fig. 30. — Part of a cross section of the proboscis sheath, about 1.8 mm. in 

 front of the beginning of the middle intestine, showing the origin of the in- 

 ner circular muscle layer from circular fibres of the proboscis sheath. The 

 innermost circular fibres of the proboscis sheath bend outward at z. and run 

 beneath the stomach, thus forming the inner circular muscle layer, x 240. 



Fig. 31.— Part of a cro~s .section of the epithelium of the oesophagus, from 

 the anterior region, showing the subepithelial gland cells, w. X 604. • 



Fig. 32. — Portion of the epithelium of the stomach, from a cross section. 

 X 604. 



Fig. 33. — Half of a cross secetion of the alimentary tract through the 

 junction of the oesophagus and the stomach. The upper part of the figure 

 shows the epithelium of the stomach, S.Ep.; the lower part that of the 

 oesophagus, (Je.JEp. A fold, /., probably represents a primitive valve. 

 X 320. 



Fig. 34. — Part of a cross section of the epithelium of the middle intestine 

 from the posterior region. The cilia are slightly diagrammatic, being 

 usually massed together in fixed preparations. X 604. 



Fig. 35. — Cross section through the "anterior region" of the proboscis. 

 X 320. 



Fig. 36. — Cross section through a portion of the "glandular ridge" of the 

 proboscis, showing several aL'gregations of rhabdiies, lihb. X 604. 



Fig. 37. — Tangential section of a portion of the proboscis from the " mid- 



47 



