04 Charles GELDERD 



FIG. 17. Transverse section through the posterior portion of the pyloric chamber. 

 The médian pièce Sj is still attached to the floor of the cavity. The grooves at 

 the side are the entrances to the grooves of the latéral faces of the pièce, they 

 are situated close to the entrance of the digestive glands into the cavity. The 

 latéral pouches are seen in trans verse section. 2/3 in, X 5. 



FIG. 18. A dissection of the posterior surface of the médian pièce S3, showing 

 the terminal spurs. D, X 3. 



FIG. 19. Transverse section, somewhat oblique, through the posterior portion 

 of the p3'loric chamber. The pièces PJ^, P^h and S5 hâve ail become free in the 

 cavity. The dorsal diverticulum with its crescent shaped lumen is seen. The over- 

 lapping folds of the diverticulum are separated from the superior lumen on account 

 of the obliquity of the section. The transition from the cuticular matrix to the 

 glandular epithelium of the digestive gland is seen at eacb side of the pièces 

 PJ.. D, X 1. 



FIG. 20. Transverse section through a part of the internai skeleton formed 

 by the transformation of original muscular fibres into chitinous substance. The bar 

 contains a pair of latéral lumina lined by a cuticle. The nuclei are those of the 

 muscle-sheath. 2/3 in, ' X 5. 



FIG. 21. Transverse section through the anterior portion of the intestine. The 

 four layers are seen. (i) a serons membrane. Ly. (2) layer of circular muscle 

 fibres. (3) longitudinal muscle fibres. (4) the epithelial layer lined by a very thin 

 chitinous cuticle cl. 1/12 Leitz X i- 



FIG. 22. Médian vertical section through the terminal portion of the intestine 

 and anus. The abrupt change from the intestinal epithelium to the loose tissue 

 which constitutes the valvules of the anus is seen. Some of the muscles attaching 

 the anus to the external ventral cuticle are shown m. The circular muscles are 

 seen in transverse section me. 2/3 in, X 3. 



FIG. 23. Transverse section through the end of the intestine. There is no 

 chitinous cuticle in this région. D, X 3. 



FIG. 24. Transverse section through the valvular part of the anus showing 

 the folds projecting into the lumen. The circular muscles me and the extrinsic bands 

 are seen m. D, X 3. 



FIG. 25. Transverse section through the anus v/hich is seen as a vertical slit 

 opening on the last segment of the body. 2/3 in, X 3. 



Macropsis. 

 FiG. 26 to 30. 



FIG. 26. Vertical section through the médian plane. It will be noticed that 

 the mouth and œsophagus are very long, the latter opening in the cardiac cham- 



