— 28 — 



foamy secretion. The gland is surrounded by tracheal sacs (A). 

 j\I— muscles; F — fat-body. Zeiss ob. AA, oc. 0. 



Fig. 8. Transverse section of the anterior part of the se- 

 cond abdominal segment of Pliymateus. The posterior part of 

 the gland (D) discharging the foamy secretion is seen. The 

 gland is limited from inside by a narrow muscle-band (M). 

 A — tracheal sac, C — chitin, F — fat-body. Zeiss AA oc. 0. 



Fig. 9. Part of the wall of the gland discharging the foamy 

 secretion in Pliymateus. C — chitin cuticle from which chiti- 

 nous deferent canals (a) lead into the gland-cells; n — nuc- 

 leus of gland-cell; pi — its plasm; nh — nuclei of matrix-cells 

 producing the chitinous cuticle of the gland (c); me — external 

 membrane of the gland. Zeiss hom. imm. V]2, oc. 4. 



Fig. 10. Part of the chitinous cuticle (c) of the same gland 

 exfoliated' from the cellular layer of the latter. Two chitinous 

 deferent canals are seen (d). Zeiss V:2 hom. imm., oc. 4. 



Fig. 11. The deeper part of the fold between the II and III 

 abdominal segment of Pliymateus cut longitudinally in the 

 upper lateral portion of the body. The hypoderm (H) in 

 the dorsal part of the fold is replaced by a layer of Stein's 

 glands forming a simple glandular area. D — gland-cells, N — 

 their nuclei, Ni — nuclei of the matrix-cells and of the cells 

 of the deferent canals. Ch — cliitiuous cuticle very folded and 

 pierced by the apertures of the deferent canals (not shown 

 in the figure). S — secretion of Stein's glands. Zeiss ob. DD, oc. 0. 



Fig. 12. Part of the glandular area of the preceding fi- 

 gure, strongly magnified (Zeiss V12 hom. imm., oc. 4). The 

 place is drawn, where the chitinous cuticle (ch) has exfoliated 

 from the cellular layers of the gland whereby the chiti- 

 nous deferent canal Tc (at A is its aperture) is clearly seen. 

 D— gland-cells, N— their nuclei, Ni— nuclear layer of the mat- 

 rix-cells and of tlie cells of the deferent canals. 



