EXPLANATION OE PLATES XXIV & XXV— Continued. 
Eig. 9. — Surface view of cells from the apical lobe, after treatment with 
nitrate of silver. 
Eig. 10. — Cells of the main lobe, after maceration in chromic acid per 
cent. ; — a. nuclei, showing network ; b. blood-vessels ; c. cuticle of blood- 
vessels ; f. indifferent connective-tissue fibres ; k. intracellular ductules ; 
1. cuticle of the ductules ; m. cuticle of the cells, x SOO diams. 
Eig. 11. — Contents of the vesicle and central and recurrent ducts. 
X 3500 diams. 
Eig. 12. — Contents of the ductules, x 3500 diams. 
Fig. 13. — Portion of a transverse section of a Leech : — l. b. v. lateral 
blood-vessel; M. L. cells of the main lobe; a. l. cells of the apical lobe; 
T. L. cells of the testis lobe ; c. d. central duct ; v. d. vesicle duct ; 
R. D. recurrent duct. a. nuclei ; h. blood-vessels ; V. empty blood-vessels ; 
d. muscular fibres in longitudinal and transverse section ; d' . circular fibres 
of the lateral blood-vessel; longitudinal fibres of the lateral blood- 
vessel ; e. cells of salivary gland ; f. indifferent connective-tissue fibres ; 
g, pigmented vaso-fibrous connective tissue; k. intracellular ductules; 
1. cuticle of the duct, x 150 diams. 
The nephridium here drawn lies on the left-hand side. The cells of the 
main lobe are seen to lie above the lateral vessel, and the central duct has 
been cut across in three places in this region. The central duct is seen 
again cut across twice, in the apical lobe, and the vesicle duct, which in the 
next section is free, is just becoming surrounded by the cells of the main 
lobe at the commencement of the lobe. The recurrent duct, which further 
on lies in the cells of the main lobe, is here surrounded by testis lobe cells 
with their peculiar irregularly-shaped ductules. 
Fig. 14. — Portion of a transverse section of a Leech, showing the vesicle 
and its excretory duct v. d. vesicle duct ; b. blood-vessels ; d. muscular 
fibres ; f. indifferent connective-tissue fibres ; g. pigmented vaso-fibrous 
connective tissue ; h. cilia, x 150 diams. 
