PLATE XX. 



Fig. 1. — Cross section of entire tail, showing position on dorsum of large 

 poison glands (p.gl.) and the mucous glands (m.gl.) chiefly on the 

 ventral side. Diagrammatic except in outlines and proportions 

 of parts. Van Gieson. 22 



Pig. -. — Mucus gland from ventral side of tail, showing large lumen (l.gl.), 

 and dark staining, angular nuclei (nue.m.e.). Lower part of 

 funnel cell (./i.e.) shown in epidermis (ep) which is not repro- 

 duced entire. Benda's iron haematoxylin. 342 



Fig. 3. — Poison gland (p.gl.) of small size partly replaced by ingrowing 

 mucous gland (m.gl.). Funnel cell (fl.e.) shown in epidermis 

 (ep.): nuclei (nue.m.e.) of mucous gland darkly stained as in 

 Fig. 1!. Benda's iron haematoxylin. 342 



Fig. 4. — Outline drawing of cross section of duct of poison gland showing 

 replacement cells of the funnel (rep.c.) rolled one within the 

 other, the funnel cell ill.c.) and the lumen of the duct [l.d.) 

 Mallory's conn, tissue stain. 875 



Fig. 5. — Portion of lower part of poison gland showing bundles of connec- 

 tive tissue ic.t.b.) passing from the inner layer of the corium 

 (i.e. I.) to the connective tissue layer of the wall of the gland 

 e.t.l.) Nuclei (nuc.p.c. ) and walls (cm.) of gland cells. Secre- 

 tion not shown in detail. Mallory's conn, tissue stain. 342 



Fig. 6. — One side of median longitudinal section of duct of poison gland 

 showing muscle fibre (m.f.) and its nucleus (m.n. land the pro- 

 longation of the fibre (prol.m.f.) into the epidermis (ep.). 

 Compare with PI. IV, Fig. 27. Mallory's conn, tissue stain. 

 280 



Fig. 7. — Branching muscle fibres (m.f.) from lower part of gland. Mal- 

 lory's conn. tiss. stain. 342 



Fig. 8. — Longitudinal section of poison gland through the mouth showing 

 two expansions of muscles (m.f.) in which the nuclei lie. and 

 portions of muscle fibres. Nucleus of funnel cell (n.fl.c.) at 

 duct (<1.). Secretion of gland not shown. Ferric-chloride 

 haematoxylin. > 342 



1262] 



