208 BULLETIN OF THE MUSEUM OF COMPARATIVE ZOOLOGY. 
Fig. 17, the forty-first section, represents the wall of the deep (dorsal) end of the 
pocket cut tangentially. 
Figs. 18 to 27 inclusive relate to the structure of the Jateral eyes. Figs. 18 and 19 
are from preparations of adult eyes. 
Fig. 18. The anterior face of a vertical axial section of the right eye (No. 2); 
compare Pl. IV. Depigmented with a solution of potassic hydrate; 
stained with Grenacher’s alcoholic borax-carmine. X 525. 
Fig. 19. Anterior face of a frontal section. Partially depigmented with potassic 
hydrate; stained with Kleinenberg’s hematoxylin. X 475. 
Figs. 20 to 27 inclusive give the structure of the eyes in young scorpions. Figs. 20 
and 21 are from material of the same age as Fig. 9. 
Fig. 20. Anterior face of a vertical axial section of left eye (No. 8). The pigment 
is unaffected, and no dye has been used. The edge of eye No. 1 is seen 
above. X 825. 
Fig. 21. Anterior face of a vertical axial section of left eye depigmented in potassic 
hydrate and stained with Grenacher’s alcoholic borax-carmine. X 825. 
PLATE IV. 
Figs. 22 to 27 inclusive are taken from the dorsal faces of a set of sections of the 
youngest embryos at hand (of the same age as those from which Figs. 15 
to 17 are taken). The sections have been depigmented with a solution 
of potassic hydrate and stained in Grenacher’s alcoholic borax-carmine. 
X 325. The figures represent the left cluster of lateral eyes. Begin- 
ning dorsally and proceeding ventrally, Fig. 22 is the first section, Fig. 
23 the third, Fig. 24 the sixth, Fig. 25 the thirteenth, Fig. 26 the six- 
teenth, and Fig. 27 the twenty-first. 
